– drugs and medicines
TRANSCRIPT
CHE-153
ORGANIC CHEMISTRY FOR HONS.
MINOR PROJECT
SUBMITTED BY- RIPUDAMAN SINGH
SECTION- R-269
GROUP- A
ROLL NO. 01
ADM. NO. 10803539
SUBMITTED TO- MR.RUPESH KUMAR
DOS- 17 NOV 2008
DEPT. LSTS
MEDICINAL CHEMISTRY – DRUGS AND MEDICINES
Medicinal or pharmaceutical chemistry is a scientific discipline at the intersection of chemistry and pharmacology involved with designing, synthesizing and developing pharmaceutical drugs. Medicinal chemistry involves the identification, synthesis and development of new chemical entities suitable for therapeutic use. It also includes the study of existing drugs, their biological properties, and their quantitative structure-activity relationships (QSAR). Pharmaceutical chemistry is focused on quality aspects of medicines and aims to assure fitness for the purpose of medicinal products.
Compounds used as medicines are overwhelmingly organic products. However, metal-containing compounds have been found to be useful as drugs. For example, the cis-platin series of platinium-containing complexes have found use as anti-cancer agents. This type of compounds are known as metal-based drugs.
Medicinal chemistry is a highly interdisciplinary science combining organic chemistry with biochemistry, computational chemistry, pharmacology, pharmacognosy, molecular biology, statistics, and physical chemistry.
Process of drug discovery
Discovery
The first step of drug discovery involves the identification of new active compounds, often called "hits", which are typically found by screening many compounds for the desired biological properties. These hits can come
from natural sources, such as plants, animals, or fungi. More often, the hits can come from synthetic sources, such as historical compound collections and combinatorial chemistry.
Optimization
The second step of drug discovery involves the synthetic modification of the hits in order to improve the biological properties of the compound pharmacophore. The quantitative structure-activity relationship (QSAR) of the pharmacophore play an important part in finding lead compounds, which exhibit the most potency, most selectivity, best pharmacokinetics and least toxicity. QSAR involves mainly physical chemistry and molecular docking tools (CoMFA and CoMSIA), that leads to tabulated data and first and second order equations. There are many theories, the most relevant being Hansch's analysis that involves Hammett electronic parameters, steric parameters and logP(lipophilicity) parameters.
Development
The final step involves the rendering the lead compounds suitable for use in clinical trials. This involves the optimization of the synthetic route for bulk production, and the preparation of a suitable drug formulation.
Current Medicinal Chemistry covers all the latest and outstanding developments in medicinal chemistry and rational drug design. Each issue contains a series of timely in-depth reviews written by leaders in the field covering a range of the current topics in medicinal chemistry. Current Medicinal Chemistry is an essential journal for every medicinal chemist who wishes to be kept informed and up-to-date with the latest and most important developments.
CHEMICALS IN MEDICINE AND HEALTH CARE-
Ayurvedic and Unani systems of treatment of diseases have been widely used in the past. But now-a-days, these systems are virtually replaced by the modern allopathic system. In all these systems, drugs used are chemical
compounds of natural or synthetic origin. It is here where chemistry has played an important role in providing newer chemicals of synthetic origin and can be used for treatment of diseases.
Chemical substances of natural or synthetic origin which are used for curing diseases and reducing suffering from pain are called medicines or drugs. The branch of science which deals with the treatment of diseases using suitable chemicals is known as chemotherapy.
In the early times, bark, leaves etc. of plants were used for treating diseases. For example, the bark of Willow tree was used to get relief from pain. Now it has been established that it contains 2-hydroxybenzoic acid (salicylic acid) which is the same compound that is obtained by hydrolysis of aspirin in our body. Similarly, the plant Rauwolfia serpentina is used even today in Ayurveda for the treatment of hypertension and high blood pressure. The medicinal properties of the plant are due to the presence of the alkaloid resperine in it. Now-a-days we, however, don’t depend only on natural drugs but also depend largely on the synthetic drugs, since they are more effective.
DRUGS AND MEDICINES- from chemistry point of view, there is no distinction between the terms drugs and medicines, i.e., all drugs are medicines and all medicines are drugs. However, our society and law make a clear-cut distinction between these two terms as follows : a medicine is a chemical substance which cures the disease, is safe to use, has negligible toxicity and does not cause addiction. In contrast, a drug is a chemical substance which also cures the disease but is habit forming, causes addiction and has serioes side effects. Thus both penicillin and heroin are medicines because penicillin is an effective antibacterial agent and heroin is a powerful pain killer but penicillin is called a medicine since it does not have addictive properties while heroin is called a drug because of its pronounced habit forming and addictive properties.
CLASSIFICATION OF MEDICINES AND DRUGS-
they are generally classified according to the purpose for which they are used. The different terms thus used along wih examples are given below-
ANALGESICS:
Any of a group of drugs of diverse chemical structure and physiological effects which are commonly used for the relief of pain. To qualify as an analgesic a drug must selectively reduce or abolish pain without causing impairment of consciousness, mental confusion, incoordination or paralysis, or other derangements of the nervous system.
The oldest and best-known of the class of narcotic alkaloid analgesics are opium, a drug obtained by extracting the juice of the poppy seed, and its most active alkaloid, morphine. Morphine and related drugs reduce or block the activation of pain neurons in the gray matter of the spinal cord, and at receptor sites in the brainstem and thalamus. In addition to their use as analgesic drugs, opiates have other biological effects such as sedation, pupillary constriction, suppression of cough reflex, respiratory depression, reduction of intestinal motility, impairment of segmental flexor reflexes, and decrease in body temperature. This functional diversity is attributed to the activation of other inhibitory systems of neurons. While morphine is the most powerful medical analgesic substance, there are many other naturally occurring alkaloids derived from opium. The best known of these is codeine. Common to all opiates is the attribute that if they are taken for weeks or months the recipient will need larger doses to obtain the same analgesic and sedative effects. This response is called tolerance. If the drug is stopped, disagreeable withdrawal or abstinence effects are experienced within hours to days. There is severe pain, sweating, salivation, hyperventilation, restlessness, and confusion. These abstinence symptoms, which are marks of habituation, pressure the addicted person to take extreme measures to obtain the narcotic in order to avoid the symptoms.
Because of the strong addictive properties of morphine and related compounds, chemists have synthesized other drugs of similar chemical structure, in the hope of securing analgesia without addiction. This effort has been only partially successful. Methadone, a drug that has been given to addicts as a substitute for morphine, is an effective analgesic when taken orally and is less addictive than morphine. Meperidine (Demerol) is a strong synthetic analgesic but definitely addictive. Other synthetic analgesics are oxycodone (Percodan), levorphanol (levodromoran), propoxyphene (Darvon), and pentazocine (Talwin). The last two of this series cause little or no addiction but, unfortunately, are not strong analgesics. Another synthetic drug, Naloxone, blocks the analgesic effect of all opiate agonists and precipitates withdrawal symptoms in addicted individuals.
Another class of analgesic drugs, which are nonnarcotic (nonaddictive), are the salicylates, the most familiar being acetylsalicylic acid (aspirin), and salicylatelike drugs such as phenylbutazone (Butazolidine), indomethacin (Indocin), acetaminophen, and phenacetin. These drugs are most effective in relieving skeletal pain due to inflammation (such as arthritis). Their analgesic properties, which are not nearly as strong as those of morphine and the synthetic opioids, are due to their action on both the peripheral and central nervous system. These drugs also have many other effects, such as reducing fever (antipyrexia) and preventing platelet agglutination. They are the most commonly used of all analgesic medications and are often combined with caffeine or a barbiturate sedative under a variety of trade names and sold for the relief of headache, backache, and so forth.
Aspirin
Naproxen
Ibuprofen
Diclophenac sodium
Codeine
Morphine
TRANQUILLIZERS AND SLEEPING PILLS (hypnotics) :
Tranquillizers are depressant drugs that slow down the central nervous system (CNS), and thus are similar to such other CNS depressants as alcohol and barbiturates.
The term "major tranquillizer" was formerly applied to drugs used to treat severe mental illnesses, such as schizophrenia. However, these drugs are now more commonly called neuroleptics; their action specifically relieves the symptoms of mental illness, and they are rarely misused for other purposes. This paper therefore deals with the anti-anxiety agents, or anxiolytics (formerly called "minor" tranquillizers).
Anti-anxiety agents share many similarities with barbiturates; both are classified as sedative/hypnotics. These newer agents were introduced under the term "tranquillizer" because, it was claimed, they provided a calming effect without sleepiness. Today, tranquillizers have largely replaced barbiturates in the treatment of both anxiety and insomnia because they are safer and more effective. The degree of sleepiness induced depends on the dosage. Tranquillizers are also used as sedatives before some surgical and medical procedures, and they are sometimes used medically during alcohol withdrawal.
Although tranquillizers do not exhibit the serious dependence characteristics of barbiturates, they nevertheless can produce tolerance and dependence. They may also be misused and abused.
The first drug to be labelled a tranquillizer was meprobamate - under the trade name Miltown - in 1954. Today, however, the most popular anti-anxiety agents are the benzodiazepines (e.g. Valium, Halcion, and Ativan). (NOTE that where a drug name is capitalized, it is a registered trade name of the manufacturer.) Since the early 1960s, the benzodiazepines have accounted for more than half the total world sales of tranquillizers. They are currently the most commonly prescribed class of psychotropic (mood-altering) drugs in Canada.
The first benzodiazepine developed was chlordiazepoxide, which is sold under such trade names as Librium and Novopoxide. The next was diazepam; it is marketed, among other brand names, as Valium, E-Pam, and Vivol. In the early 1970s diazepam was the most widely prescribed drug in North America. Now Halcion and Ativan - drugs from the same family as diazepam but eliminated more rapidly from the body - account for most benzodiazepine prescriptions. There are 14 different benzodiazepines currently available in Canada. Some are prescribed as anti-anxiety drugs (e.g. Valium, Librium); others are recommended as sleeping medications (e.g. Dalmane, Somnol, Novoflupam, and Halcion).
Barbituaric acid Barbital
Chlordiazepoxide
Diazepam (Valium)
Meprobamate
Serotonin
Seconal
Luminal Nembutal
Equanil
ANTIPSYCHOTICS:
Definition
Antipsychotic drugs are a class of medicines used to treat psychosis and other mental and emotional conditions.
Description
The antipsychotic agents may be divided by chemical class. The phenothiazines are the oldest group, and include chlorpromazine (Thorazine), mesoridazine (Serentil), prochlorperazine (Compazine), and thioridazine (Mellaril). These drugs are essentially similar in action and adverse effects. They may also be used as anti-emetics, although prochlorperazine is the drug most often used for this indication.
The phenylbutylpiperadines are haloperidol (Haldol) and pimozide (Orap). They find primary use in control of Tourette's syndrome. Haloperidol has been extremely useful in controlling aggressive behavior.
The debenzapine derivatives, clozapine (Clozaril), loxapine (Loxitane), olanzapine (Zyprexa) and quetiapine (Seroquel), have been effective in controlling psychotic symptoms that have not been responsive to other classes of drugs.
The benzisoxidil group is composed of resperidone (Resperidal) and ziprasidone (Geodon). Resperidone has been found useful for controlling bipolar mood disorder, while ziprasidone is used primarily as second-line treatment for schizophrenia.
In addition to these drugs, the class of antipsychotic agents includes lithium carbonate (Eskalith, Lithonate), which is used for control of bipolar mood disorder, and thiothixene (Navane), which is used in the treatment of psychosis.
Terminology
Antipsychotics are also referred to as neuroleptic drugs, or simply neuroleptics. The word neuroleptic is derived from Greek; neuro refers to the nerves and lept means "to take hold of". Thus the word means "taking hold of one's nerves". This term reflected the fact that the drugs commonly made movement more difficult and sluggish, which clinicians believed indicated that a dose was high enough.[citation needed] The lower doses used currently have resulted in reduced incidence of motor side effects and sedation and the term is less commonly used than in the past.
Antipsychotics are broadly divided into two groups, the typical or first generation antipsychotics and the atypical or second generation antipsychotics. There are also dopamine partial agonists, which are often categorized as atypicals.
Typical antipsychotics are also sometimes referred to as major tranquilizers, because some of them can tranquilize and sedate. This term is increasingly disused as the terminology implies a connection with benzodiazepines ("minor" tranquilizers) when none exists.
Usage
Common conditions with which antipsychotics might be used include schizophrenia, mania and delusional disorder. They might be used to counter psychosis associated with a wide range of other diagnoses. Antipsychotics may also be used in mood disorder (e.g. bipolar disorder) even when no signs of psychosis are present. Some antipsychotics (haloperidol, pimozide) are used off-label to treat Tourette syndrome.
Typical antipsychotics
o Phenothiazines :
Chlorpromazine (Thorazine) Fluphenazine (Prolixin) - Available in decanoate (long acting)
form
Perphenazine (Trilafon) Prochlorperazine (Compazine) Thioridazine (Mellaril) Trifluoperazine (Stelazine) Mesoridazine Promazine Triflupromazine (Vesprin) Levomepromazine (Nozinan)
o Thioxanthenes : Chlorprothixene Flupenthixol (Depixol and Fluanxol) Thiothixene (Navane) Zuclopenthixol (Clopixol and Acuphase)
o Butyrophenones : Haloperidol (Haldol) - Available in decanoate (long acting) form Droperidol Pimozide (Orap) - Used to treat Tourette syndrome Melperone
Chlorpromazine Haldoperidol Quetiapine
Haldol Thorazine
Zyprexa
STIMULANTS:
any substance that causes an increase in activity in various parts of the nervous system or directly increases muscle activity. Cerebral, or psychic, stimulants act on the central nervous system and provide a temporary sense of alertness and well-being as well as relief from fatigue. Drugs such as caffeine and the amphetamines belong in this category, and several groups of drugs chemically similar to antihistamines and phenothiazines also act as mild psychic stimulants (see psychopharmacology). Cocaine, besides its effect as a local anesthetic, also stimulates the central nervous system, producing excitement and erratic behavior. The hallucinogenic drugs are also central nervous system stimulants.
A second class of stimulants that affect the medulla and spinal cord includes derivatives of niacinamide (nicotinic acid amide) and other chemically diverse compounds; they are sometimes used to speed the return to wakefulness after anesthesia or to counteract barbiturate poisoning. Ammonia, in smelling salts, is also a medullary stimulant; the alkaloid strychnine is a spinal-cord stimulant.
Other substances act mainly on the autonomic nervous system. Drugs that stimulate the parasympathetic portion of the autonomic nervous system, such as pilocarpine, physostigmine, and neostigmine, cause contracted pupils, salivation and sweating, slowed heartbeat, and lowered blood pressure. Drugs such as norepinephrine, epinephrine, and other catecholamines and synthetic analogs stimulate the sympathetic portion of the autonomic nervous system, resulting in dilated pupils, rapid heartbeat, and increased blood pressure. Because the sympathetic and parasympathetic systems have opposing physiological effects, stimulation of one system amounts to depression of the other. Some of the alkaloids from the ergot fungus act by direct stimulation of smooth muscle, inducing contractions in uterine and intestinal muscle.
Functions-
Stimulants increase the activity of either the sympathetic nervous system, the central nervous system (CNS) or both. Some stimulants produce a sense
of euphoria, in particular the stimulants which exert influence on the CNS. Stimulants are used therapeutically to increase or maintain alertness, to counteract fatigue in situations where sleep is not practical (e.g. while operating vehicles), to counteract abnormal states that diminish alertness consciousness, (such as in narcolepsy), to promote weight loss (phentermine) as well as to enhance the ability to concentrate in people diagnosed with attentional disruptions (especially ADHD). Occasionally, they are also used to treat depression. Stimulants are sometimes used to boost endurance and productivity as well as to suppress appetite. The euphoria produced by some stimulants leads to their recreational use, although this is illegal in the majority of jurisdictions.
Caffeine, found in beverages such as coffee and soft drinks, as well as nicotine, which is found in tobacco, are among some of the world's most commonly used stimulants.
Examples of other well known stimulants include ephedrine, amphetamines, cocaine, methylphenidate, MDMA, and modafinil. Stimulants are commonly referred in slang as "uppers".
Adrenaline Amphetamine
Caffeine Cocaine
Methamphetamine Nicotine
HALLUCINOGENS:
The general group of pharmacological agents commonly known as hallucinogens can be divided into three broad categories: psychedelics, dissociatives, and deliriants. These classes of psychoactive drugs have in common that they can cause subjective changes in perception, thought, emotion and consciousness. Unlike other psychoactive drugs, such as stimulants and opioids, the hallucinogens do not merely amplify familiar states of mind, but rather induce experiences that are qualitatively different from those of ordinary consciousness. These experiences are often compared to non-ordinary forms of consciousness such as trance, meditation, conversion experiences, and dreams.
One thing that most of these drugs do not do, despite the ingrained usage of the term hallucinogen, is to cause hallucinations. Hallucinations, strictly speaking, are perceptions that have no basis in reality, but that appear entirely realistic. A typical "hallucination" induced by a psychedelic drug is more accurately described as a modification of regular perception, and the subject is usually quite aware of the illusory and personal nature of their perceptions. Some less common drugs, such as dimethyltryptamine and atropine, may cause hallucinations in the proper sense.
Psychedelics, dissociatives, and deliriants have a long history of use within medicinal and religious traditions around the world. They are used in shamanic forms of ritual healing and divination, in initiation rites, and in the religious rituals of syncretistic movements such as União do Vegetal, Santo Daime, and the Native American Church. When used in religious practice, psychedelic drugs, as well as other substances like tobacco, are referred to as entheogens.
Starting in the mid-20th century, psychedelic drugs have been the object of extensive attention in the Western world. They have been and are being explored as potential therapeutic agents in treating depression, Post-traumatic Stress Disorder, Obsessive-compulsive Disorder, alcoholism,
opioid addiction, cluster headaches, and other ailments. Early military research focused on their use as incapacitating agents. Intelligence agencies tested these drugs in the hope that they would provide an effective means of interrogation, with little success.
Yet the most popular, and at the same time most stigmatized, use of psychedelics in Western culture has been associated with the search for direct religious experience, enhanced creativity, personal development, and "mind expansion". The use of psychedelic drugs was a major element of the 1960s counterculture, where it became associated with various political movements and a general atmosphere of rebellion and strife between generations.
Psychedelics- any drug with perception-altering effects such as LSD, psilocybin, DMT, 2C-B, mescaline, and DOM as well as a panoply of other tryptamines, phenethylamines and yet more exotic chemicals, all of which appear to act mainly on the 5-HT2A receptor. Common herbal sources of psychedelics include psilocybe mushrooms, various ayahuasca preparations, peyote, San Pedro cactus, and the seeds of morning glory and Hawaiian baby woodrose.
Dissociatives- Dissociatives are drugs that reduce (or block) signals to the conscious mind from other parts of the brain, typically (but not necessarily, or limited to) the physical senses. Such a state of sensory deprivation can facilitate self exploration, hallucinations, and dreamlike states of mind which may resemble some psychedelic mindstates. Essentially similar states of mind can be reached via contrasting paths—psychedelic or dissociative.
The primary dissociatives are similar in action to PCP (angel dust) and include ketamine (an anaesthetic), and dextromethorphan (an active ingredient in many cough syrups). Also included are nitrous oxide, and muscimol from the Amanita muscaria (fly agaric) mushroom.
Deliriants- The deliriants (or anticholinergics) are a special class of dissociative which are antagonists for the acetylcholine receptors (unlike muscarine and nicotine which are agonists of these receptors). Deliriants are sometimes called true hallucinogens, because they do cause hallucinations
in the proper sense: a user may have conversations with people who aren't there, or become angry at a 'person' mimicking their actions, not realizing it is their own reflection in a mirror.[citation needed] They are called deliriants because their effects are similar to the experiences of people with delirious fevers. While dissociatives can produce effects similar to lucid dreaming (where one is consciously aware they are dreaming), the deliriants have effects akin to sleepwalking (where one doesn't remember what happened during the experience).
Included in this group are such plants as deadly nightshade, mandrake, henbane and datura, as well as a number of pharmaceutical drugs when taken in very high doses such as the antihistamine diphenhydramine (Benadryl) and the antiemetic dimenhydrinate (Dramamine or Gravol).
LSD
THC
ANTIMICROBIALS:
Antimicrobial drugs are drugs designed to kill, or prevent the growth of microorganisms (bacteria, fungi, and viruses). Bacteria, fungi, and viruses are responsible for almost all of the common infectious diseases found in North America from athlete's foot, to AIDS, to ulcers (as of 2001). Interestingly enough, many disorders formerly thought to be caused by other factors, like stress, are now known to be caused by bacteria. For example, it has been shown that many ulcers are caused by the bacteria Helicobacter pylori, and not by stress, as many originally thought. Thus, antimicrobials represent an important part of medicine today.
The history of antimicrobials begins with the observations of Pasteur and Joubert, who discovered that one type of bacteria could prevent the growth of another. They did not know at that time that the reason one bacteria failed to grow was that the other bacteria was producing an antibiotic. Technically, antibiotics are only those substances that are produced by one microorganism that kill, or prevent the growth, of another microorganism. Of course, in today's common usage, the term antibiotic is used to refer to almost any drug that cures a bacterial infection. Antimicrobials include not just antibiotics, but synthetically formed compounds as well.
The discovery of antimicrobials like penicillin and tetracycline paved the way for better health for millions around the world. Before 1941, the year penicillin was discovered, no true cure for gonorrhea, strep throat, or pneumonia existed. Patients with infected wounds often had to have a wounded limb removed, or face death from infection. Now, most of these infections can be easily cured with a short course of antimicrobials.
However, the future effectiveness of antimicrobial therapy is somewhat in doubt. Microorganisms, especially bacteria, are becoming resistant to more and more antimicrobial agents. Bacteria found in hospitals appear to be
especially resilient, and are causing increasing difficulty for the sickest patients–those in the hospital. Currently, bacterial resistance is combated by the discovery of new drugs. However, microorganisms are becoming resistant more quickly than new drugs are being found, Thus, future research in antimicrobial therapy may focus on finding how to overcome resistance to antimicrobials, or how to treat infections with alternative means.
Cations and elements
Many heavy metal cations such as Hg2+, Cu2+, and Pb2+ have antimicrobial activities, but are also very toxic to other living organisms, thus making them unsuitable for treating infectious diseases.
Nitrofuranes
1. Chemical structure The nitrofuranes have encommun a core furane substituted in position 5 by an essential function nitroo for the antibiotic activity.
2. Mechanism of action - Activation of antibiotic- The nitrofuranes acquire their antibactérienne activity after the enzymatic reduction of their function nitro, catalysed by bacterial réductases, which ensures their specificity of action. This mechanism is in common with nitroimidazoles; the difference lies in the reducing potential necessary to obtain the various intermediaries, and thus in the suscpetibles bacteria to activate the product.
ANTISEPTICS:
A drug used to destroy or prevent the growth of infectious microorganisms on or in the human or animal body, that is, on living tissue. Many chemical substances have been employed as antiseptics.
Iodine is the most important of the halogens used as an antiseptic. Tincture of iodine (iodine in an alcohol solution) has been employed widely as a preoperative antiseptic and in first aid. Tincture of iodine is germicidal by laboratory test in 0.02% concentration, but 2.0% solutions are usually employed in surgery and first aid.
Compounds of mercury were used to prevent infection before the germ theory of disease was established. Because of their high toxicity and severe caustic action, such inorganic mercurials as mercuric chloride, mercuric oxycyanide, and potassium mercuric iodide have been largely replaced by certain organic mercury compounds. Organic mercurial compounds are far less toxic and are nonirritating in concentrated solutions. They are highly bacteriostatic, and in concentrated solutions germicidal as well. They are also nonspecific in antimicrobial activity.
Essential oils have been defined as odoriferous oily substances obtained from such natural sources as plants by steam distillation. Essential oils in alcoholic solutions also were early employed in place of the carbolic acid solution of Lister, and because of the toxic and corrosive action of mercury bichloride, they also replaced this compound. Alcoholic solution of essential oils was first developed in 1881 and was admitted as liquor antisepticus to the U.S. Pharmacopoeia in 1900 and to the National Formulary IV in 1916. Alcoholic solutions of essential oils as represented by liquor antisepticus
have proved effective in a wide variety of clinical applications and in first aid.
Silver compounds have been widely used for a variety of purposes. Because of the bland nature of most of these compounds, they have been successfully used in the eyes, nose, throat, urethral tract, and other organs. The most widely used silver compounds are silver nitrate, ammoniacal silver nitrate solution, silver picrate, and certain colloidal silver preparations such as strong protein silver and mild silver protein. These are effective germicides of low tissue toxicity and are not counteracted by organic matter.
Such compounds as ethyl alcohol and isopropyl alcohol are germicidal rather than bacteriostatic and are effective against the vegetative forms of bacteria and virus, but do not kill spores. Ethyl alcohol in 62.5–70% solution is most commonly used, being widely employed for disinfecting the skin before hypodermic injections and other skin punctures. Isopropyl alcohol is equal, if not superior, to ethyl alcohol and is widely used for degerming the skin and for disinfecting oral thermometers. Alcohols are also widely used in other antiseptic preparations, in which they serve to lower the surface tension and to promote spreading and penetration.
Bisphenol compounds such as dichlorophene and tetrachlorophene are essentially bacteriostatic agents and are weaker as germicides. They have proved quite effective as skin-degerming agents, when used in soaps and other detergents, and as mildew-preventing formulations. The halogenated form, such as dichlorophene, tetrachlorophene, hexachlorophene, and bithionol, is most commonly employed. When used repeatedly on the skin, as in soaps and detergents, bisphenols have a tendency to remain for long periods, thus reducing skin bacteria to a significant degree. For this purpose they are especially useful in preoperative hand washing.
Quaternary ammonium compounds have high germicidal activity. Although they are more properly classified as surfaceactive disinfectants, some of them are employed in certain antiseptic formulations, for instance, Zephiran, especially suited for use on the skin, and Cepacol, for mucous surfaces. Nontoxic and nonirritating, they may be used in place of alcohol after preoperative scrub-up.
Chloroxylenol
DISINFECTANTS:
Disinfectants are antimicrobial agents that are applied to non-living objects to destroy microorganisms, the process of which is known as disinfection. Disinfectants should generally be distinguished from antibiotics that destroy microorganisms within the body, and from antiseptics, which destroy microorganisms on living tissue. Sanitisers are high level disinfectants that kill over 99.9% of a target microorganism in applicable situations. Very few disinfectants and sanitisers can sterilise (the complete elimination of all microorganisms), and those that can depend entirely on their mode of application. Bacterial endospores are most resistant to disinfectants, however some viruses and bacteria also possess some tolerance.
By far the most cost-effective home disinfectant is the commonly used chlorine bleach (a 5% solution of Sodium hypochlorite) which is effective against most common pathogens, including such difficult organisms tuberculosis (mycobacterium tuberculosis), hepatitis B and C, fungi, and antibiotic-resistant strains of staphylococcus and enterococcus.
Types of disinfectants
Alcohols
Alcohols, usually ethanol or isopropanol, are wiped over benches and skin and allowed to evaporate for quick disinfection. They have wide microbiocidal activity, are non corrosive, but can be a fire hazard. They also have limited residual activity due to evaporation, which results in brief contact times, and have a limited activity in the presence of organic material. Alcohols are more effective combined with purified water—70% isopropyl alcohol or 62% ethyl alcohol is more effective than 95% alcohol. Alcohol is not effective against fungal or bacterial spores.
Aldehydes
Aldehydes, such as Glutaraldehyde, have a wide microbiocidal activity and are sporocidal and fungicidal. They are partly inactivated by organic matter and have slight residual activity.
Halogens
Chloramine is used in drinking water treatment instead of chlorine because it produces fewer disinfection byproducts.
Chlorine is used to disinfect swimming pools, and is added in small quantities to drinking water to reduce waterborne diseases.
Hypochlorites (Sodium hypochlorite), often in the form of common household bleach, are used in the home to disinfect drains, and toilets. Other hypochlorites such as calcium hypochlorite are also used, especially as a swimming pool additive. Hypochlorites yield an aqueous solution of hypochlorous acid that is the true disinfectant. Hypobromite solutions are also sometimes used.
Iodine is usually dissolved in an organic solvent or as Lugol's iodine solution. It is used in the poultry industry. It is added to the birds' drinking water. Although no longer recommended because it increases scar tissue formation and increases healing time, tincture of iodine has also been used as an antiseptic for skin cuts and scrapes.
Oxidizing agents
Oxidizing agents act by oxidising the cell membrane of microorganisms, which results in a loss of structure and leads to cell lysis and death.
Phenolics
Phenolics are active ingredients in some household disinfectants. They are also found in some mouthwashes and in disinfectant soap and handwashes.
Quaternary ammonium compounds
Quaternary ammonium compounds (Quats), such as benzalkonium chloride, are a large group of related compounds. Some have been used as low level disinfectants. They are effective against bacteria, but not against some species of Pseudomonas bacteria or bacterial spores. Quats are biocides which also kill algae and are used as an additive in large-scale industrial water systems to minimize undesired biological growth. Quaternary ammonium compounds can also be effective disinfectants against enveloped viruses.
ANTIBIOTICS:
Definition
Antibiotics may be informally defined as the sub-group of anti-infectives that are derived from bacterial sources and are used to treat bacterial infections. Other classes of drugs, most notably the sulfonamides, may be effective antibacterials. Similarly, some antibiotics may have secondary uses, such as the use of demeclocycline (Declomycin, a tetracycline derivative) to treat the syndrome of inappropriate antidiuretic hormone (SIADH) secretion. Other antibiotics may be useful in treating protozoal infections.
Description
Classification
Although there are several classification schemes for antibiotics, based on bacterial spectrum (broad versus narrow) or route of administration (injectable versus oral versus topical), or type of activity (bactericidal vs. bacteriostatic), the most useful is based on chemical structure. Antibiotics within a structural class will generally show similar patterns of effectiveness, toxicity, and allergic potential.
PENICILLINS. The penicillins are the oldest class of antibiotics, and have a common chemical structure which they share with the cephalopsorins. The two groups are classed as the beta-lactam antibiotics, and are generally bacteriocidal—that is, they kill bacteria rather than inhibiting growth. The
penicillins can be further subdivided. The natural pencillins are based on the original penicillin G structure; penicillinase-resistant penicillins, notably methicillin and oxacillin, are active even in the presence of the bacterial enzyme that inactivates most natural penicillins. Aminopenicillins such as ampicillin and amoxicillin have an extended spectrum of action compared with the natural penicillins; extended spectrum penicillins are effective against a wider range of bacteria. These generally include coverage for Pseudomonas aeruginaosa and may provide the penicillin in combination with a penicillinase inhibitor.
CEPHALOSPORINS. Cephalosporins and the closely related cephamycins and carbapenems, like the pencillins, contain a beta-lactam chemical structure. Consequently, there are patterns of cross-resistance and cross-allergenicity among the drugs in these classes. The "cepha" drugs are among the most diverse classes of antibiotics, and are themselves subgrouped into 1st, 2nd and 3rd generations. Each generation has a broader spectrum of activity than the one before. In addition, cefoxitin, a cephamycin, is highly active against anaerobic bacteria, which offers utility in treatment of abdominal infections. The 3rd generation drugs, cefotaxime, ceftizoxime, ceftriaxone and others, cross the blood-brain barrier and may be used to treat meningitis and encephalitis. Cephalopsorins are the usually preferred agents for surgical prophylaxis.
FLUROQUINOLONES. The fluroquinolones are synthetic antibacterial agents, and not derived from bacteria. They are included here because they can be readily interchanged with traditional antibiotics. An earlier, related class of antibacterial agents, the quinolones, were not well absorbed, and could be used only to treat urinary tract infections. The fluroquinolones, which are based on the older group, are broad-spectrum bacteriocidal drugs that are chemically unrelated to the penicillins or the cephaloprosins. They are well distributed into bone tissue, and so well absorbed that in general they are as effective by the oral route as by intravenous infusion.
TETRACYCLINES. Tetracyclines got their name because they share a chemical structure that has four rings. They are derived from a species of Streptomyces bacteria. Broad-spectrum bacteriostatic agents, the tetracyclines may be effective against a wide variety of microorganisms, including rickettsia and amebic parasites.
MACROLIDES. The macrolide antibiotics are derived from Streptomyces bacteria, and got their name because they all have a macrocyclic lactone chemical structure. Erythromycin, the prototype of this class, has a spectrum and use similar to penicillin. Newer members of the group, azithromycin and clarithyromycin, are particularly useful for their high level of lung penetration. Clarithromycin has been widely used to treat Helicobacter pylori infections, the cause of stomach ulcers.
OTHERS. Other classes of antibiotics include the aminoglycosides, which are particularly useful for their effectiveness in treating Pseudomonas aeruginosa infections;
the lincosamindes, clindamycin and lincomycin, which are highly active against anaerobic pathogens. There are other, individual drugs which may have utility in specific infections.
HISTORY- Although potent antibiotic compounds for treatment of human diseases caused by bacteria (such as tuberculosis, bubonic plague, or leprosy) were not isolated and identified until the twentieth century, the first known use of antibiotics was by the ancient Chinese over 2,500 years ago.[1] Many other ancient cultures, including the ancient Egyptians and ancient Greeks already used molds and plants to treat infections, owing to the production of antibiotic substances by these organisms. At that time, however, the compounds having antibiotic activity and present in moulds or plants were unknown.
The antibiotic properties of Penicillium sp. were first described in France by Ernest Duchesne in 1897. However, his work went by without much notice from the scientific community until Alexander Fleming's discovery of Penicillin (see below).
Modern research on antibiotic therapy began in Germany with the development of the narrow-spectrum antibiotic Salvarsan by Paul Ehrlich in 1909, for the first time allowing an efficient treatment of the then-widespread problem of Syphilis. The drug, which was also effective against other spirochaetal infections, is no longer in use in modern medicine.
Antibiotics were further developed in Britain following the re-discovery of Penicillin in 1928 by Alexander Fleming. More than ten years later, Ernst
Chain and Howard Florey became interested in his work, and came up with the purified form of penicillin. The three shared the 1945 Nobel Prize in Medicine.
"Antibiotic" was originally used to refer only to substances extracted from a fungus or other microorganism, but has come to also include the many synthetic and semi-synthetic drugs that have antibacterial effects.
Chloramphenicol
Penicillin
Ofloxacin
Streptomycin Tetracycline
SULPHA DRUGS:
The term sulfa drug refers to the class of medications called sulfonamides. This class includes several antibiotics, including sulfamethoxazole, sulfasalazine, and sulfacetamide, among others.
It is important to make a distinction between sulfa drugs and other sulfur-containing drugs and additives, such as sulfates and sulfites, which are chemically unrelated to the sulfonamide group, and do not cause the same hypersensitivity reactions seen in the sulfonamides.
Functions
These antibiotics are used to treat pneumocystis jiroveci pneumonia, urinary tract infections, shigellosis, and certain protozoan infections.
The sulfonamide chemical moiety is also present in other medications that are not antimicrobials, including thiazide diuretics (including hydrochorothiazide, metolazone, and indapamide, among others),
sulfonylureas (including glipizide, glyburide, among others), and acetazolamide.
Sulfasalazine, in addition to its use as an antibiotic, is also utilized in the treatment of inflammatory bowel disease.
Sulphadiazine
Sulphaguanidine
ANTIFERTILITY DRUGS:
Chemical substances which are used to check pregnancy in women are called anti-fertility drugs or birth control drugs or oral contraceptives. These control the female menstrual cycle and ovulation.
All these drugs contain chemicals related to female sex hormones having a steroid ring structure. Most of these contain a combination of a synthetic estrogen and a progesterone derivative which are more potent than the natural hormones. For example, a common brand name Enovid E contains norethindrone (a progesterone derivative) and mestranol or ethinyestradiol monomethyl ether (an estrogen). Mifepristone is a synthetic steroid that blocks the effects of progesterone and is used as a ‘morning after pill’ in
many countries. All such drugs are expected to have side effects and hence should be used only under proper medical advice.
Mifepristone
Mestranol
Estradiol
Norethindrone
ANTIHISTAMINES:
A type of drug that inhibits the combination of histamine with histamine receptors. These drugs are termed either H-1 or H-2 receptor antagonists depending on which type of histamine receptor is involved. H-1 receptor antagonists are used largely for treating allergies, and H-2 receptor antagonists are used to treat peptic ulcer disease and related conditions.
The primary therapeutic use of H-1 receptor antagonists is to antagonize the effects of histamine released from cells by antigen-antibody reactions; they can thus inhibit histamine-induced effects, such as bronchoconstriction, skin reactions, for example, wheals and itching, and nasal inflammation. These drugs, therefore, are quite effective in reducing allergy signs and symptoms, especially if they are administered before contact with the relevant antigen; however they are not effective in treating asthma. Their effects vary widely, both among the drugs and from individual to individual; in young children excitement may be seen. Another common set of effects caused by many of these drugs, including dry mouth, blurred vision, and urinary retention, can be ascribed to their anticholinergic actions. H-1 receptor antagonists have low toxicity. The chief adverse effect is sedation. Overdoses of H-1 receptor antagonists may be associated with excitement or depression, and although there is no pharmacologic antidote for these drugs, good supportive care should be adequate in managing cases of poisoning. See also Allergy; Antigen-antibody reaction; Asthma; Sedative.
H-2 receptor antagonists are much newer. Histamine stimulates gastric acid secretion by combining with H-2 receptors. By preventing this combination, H-2 antagonists can reduce acid secretion in the stomach, an effect that makes these drugs useful in managing various conditions, such as peptic ulcer disease. See also Ulcer.
Other conditions in which H-2 antagonists are used to lower gastric acidity include reflux esophagitis, stress ulcers, and hypersecretory states such as the Zollinger-Ellison syndrome, in which tumor cells secrete large amounts of the hormone gastrin, which stimulates gastric acid secretion. In these conditions, administration of H-2 antagonists reduces symptoms and promotes healing.
The toxicity of H-2 antagonists is quite low, and adverse effects are reported by only 1-2% of patients. The most common side effects are gastrointestinal upsets, including nausea, vomiting, and diarrhea.
Pharmacology
In allergic reactions an allergen (a type of antigen) interacts with and cross-links surface IgE antibodies on mast cells and basophils. Once the mast cell-antibody-antigen complex is formed, a complex series of events occurs that eventually leads to cell degranulation and the release of histamine (and other chemical mediators) from the mast cell or basophil. Once released, histamine can react with local or widespread tissues through histamine receptors.
Histamine, acting on H1-receptors, produces pruritus, vasodilatation, hypotension, flushing, headache, tachycardia, bronchoconstriction, increases vascular permeability, potentiates pain, and more. [2]
FIRST GENERATION ANTIHISTAMINES-
First generation antihistamines include Diphenhydramine (Benadryl); Carbinoxamine (Clistin); Clemastine (Tavist);Chlorpheniramine (Chlor-Trimeton)and Brompheniramine (Dimetane).
While H1-antihistamines help against these effects, they only work if taken before contact with the allergen. In severe allergies, such as anaphylaxis or angioedema, these effects may be so severe as to be life-threatening. Epinephrine, often in the form of an autoinjector (Epi-pen), is required by people with such hypersensitivities.
Class Description Examples
Ethylenediamines
Ethylenediamines were the first group of clinically-effective H1-antihistamines developed.
Mepyramine (pyrilamine)
Antazoline Ethanolamines Diphenhydramine was the Diphenhydramine
prototypical agent in this group. Significant anticholinergic adverse effects, as well as sedation, are observed in this group but the incidence of gastrointestinal adverse effects is relatively low. [3] [6]
Carbinoxamine Doxylamine Clemastine
Dimenhydrinate
Alkylamines
The isomerism is a significant factor in the activity of the agents in this group. E-triprolidine, for example, is 1000-fold more potent than Z-triprolidine. This difference relates to the positioning and fit of the molecules in the histamine H1-receptor binding site. [6] Alkylamines are considered to have relatively fewer sedative and gastrointestinal adverse effects, but relatively greater incidence of paradoxical CNS stimulation. [3]
Pheniramine Chlorphenamine
(chlorpheniramine) Dexchlorpheniramine Brompheniramine
Triprolidine
Piperazines
These compounds are structurally-related to the ethylenediamines and the ethanolamines; and produce significant anticholinergic adverse effects. Compounds from this group are often used for motion sickness, vertigo, nausea and vomiting. The second-generation H1-antihistamine cetirizine also belongs to this chemical group. [6]
Cyclizine Chlorcyclizine Hydroxyzine
Meclizine
Tricyclics and These compounds differ Promethazine
Tetracyclics
from the phenothiazine antipsychotics in the ring-substitution and chain characteristics. (Nelson, 2002) They are also structurally-related to the tricyclic antidepressants (and tetracyclics), explaining the antihistaminergic adverse effects of those three drug classes and also the poor tolerability profile of tricyclic H1-antihistamines. The second-generation H1-antihistamine loratadine was derived from compounds in this group.
Alimemazine (trimeprazine)
Cyproheptadine Azatadine
Ketotifen
Common structural features
Two aromatic rings, connected to a central carbon, nitrogen or CO Spacer between the central X and the amine, usually 2-3 carbons in
length, linear, ring, branched, saturated or unsaturated Amine is substituted with small alkyl groups eg CH3
X = N, R1 = R2 = small alkyl groupsX = CX = CO
Chirality at X can increase both the potency and selectivity for H1-receptors
For maximum potency, the two aromatic rings should be orientated in different planes.
o for example, tricyclic ring system is slightly puckered and the two aromatic rings lie in different geometrical planes, giving the drug a very high potency.
Second-generation and third-generation (selective, non-sedating)
Second generation antihistamines are newer drugs that are much more selective for peripheral H1 receptors in preference to the central nervous system histaminergic and cholinergic receptors. This selectivity significantly reduces the occurrence of adverse drug reactions compared with first-generation agents, while still providing effective relief of allergic conditions.
Third generation antihistamines are the active enantiomer (levocetirizine) or metabolite (desloratadine & fexofenadine) derivatives of second-generation drugs intended to have increased efficacy with fewer adverse drug reactions. Indeed, fexofenadine is associated with a decreased risk of cardiac arrhythmia compared to terfenadine. However, there is little evidence for any advantage of levocetirizine or desloratadine, compared to cetirizine or loratadine respectively.
Systemic, second-generation
Acrivastine Astemizole Cetirizine Loratadine Mizolastine Terfenadine (withdrawn from most markets due to risk of cardiac
arrhythmias and replaced with fexofenadine)
Topical, second-generation
Azelastine Levocabastine Olopatadine
Systemic, third generation
Levocetirizine Desloratadine
Fexofenadine
Common structural features
Structure of these drugs varies from case to case. There are no common structural features.
Chlorpheniramine
Promethazine
Diphenylhydramine
ANTACIDS:
An antacid is any substance, generally a base, which counteracts stomach acidity. In other words, antacids are stomach acid neutralizers.
Action mechanism
Antacids perform a neutralization reaction, i.e. they buffer gastric acid, raising the pH to reduce acidity in the stomach. When gastric hydrochloric acid reaches the nerves in the gasitrointestinal mucosa, they signal pain to the central nervous system. This happens when these nerves are exposed, as in peptic ulcers. The gastric acid may also reach ulcers in the esophagus or the duodenum.
Other mechanisms may contribute, such as the effect of aluminum ions inhibiting smooth muscle cell contraction and delaying gastric emptying.
Indications
Antacids are taken by mouth to relieve heartburn, the major symptom of gastroesophageal reflux disease, or acid indigestion. Treatment with antacids alone is symptomatic and only justified for minor symptoms. Peptic ulcers may require H2-receptor antagonists or proton pump inhibitors.
The usefulness of many combinations of antacids is not clear, although the combination of magnesium and aluminum salts may prevent alteration of bowel habits.
Side effects
Aluminum hydroxide: may lead to the formation of insoluble aluminum-phosphate-complexes, with a risk for hypophosphatemia and osteomalacia. Although aluminum has a low gastrointestinal absorption, accumulation may occur in the presence of renal insufficiency. Aluminum-containing drugs may cause obstipation.
Magnesium hydroxide: has laxative properties. Magnesium may accumulate in patients with renal failure leading to hypermagnesemia, with cardiovascular and neurological complications.
Carbonate: regular high doses may cause alkalosis, which in turn may result in altered excretion of other drugs, and kidney stones. A chemical reaction between the carbonate and hydrochloric acid may produce carbon dioxide gas. This causes gastric distension which may not be well tolerated.
Calcium: compounds containing calcium may increase calcium output in the urine, which might be associated to renal stones. Calcium salts may cause Constipation.
Sodium: increased intake of sodium may be deleterious for arterial hypertension, heart failure and many renal diseases.
Interactions
Altered pH or complex formation may alter the bioavailability of other drugs, such as tetracycline. Urinary excretion of certain drugs may also be affected.
Drug names
Examples of antacids (brand names may vary in different countries).
Aluminum hydroxide (Amphojel®, AlternaGEL®) Magnesium hydroxide (Phillips’® Milk of Magnesia) Aluminum hydroxide and magnesium hydroxide (Maalox®, Mylanta®) Aluminum carbonate gel (Basaljel®) Calcium carbonate (Alcalak®, Calcium Rich TUMS®, Quick-Eze®,
Rennie®, Titralac®, Rolaids®) Sodium bicarbonate (Bicarbonate of soda, Alka-Seltzer®) Hydrotalcite (Mg6Al2(CO3)(OH)16 · 4(H2O); Talcid®) Bismuth subsalicylate (Pepto-Bismol) Magaldrate + Simethicone (Pepsil)
Major Drug Groups
Gastrointestinal tract (A)Antacids • Antiemetics • H₂-receptor antagonists • Proton pump inhibitors • Laxatives • Antidiarrhoeals
Blood and blood forming organs (B)Anticoagulants • Antiplatelets • Thrombolytics
Cardiovascular system (C)
Antiarrhythmics • Antihypertensives • Diuretics • Vasodilators • Antianginals • Beta blockers • Angiotensin converting enzyme inhibitors • Antihyperlipidemics
Skin (D)Antipruritics
Reproductive system (G)Hormonal contraception • Fertility agents • Selective estrogen receptor modulators • Sex hormones
Endocrine system (H)Anti-diabetics • Corticosteroids • Sex hormones • Thyroid hormones
Infections and Infestations (J, P)Antibiotics • Antivirals • Vaccines • Antifungals • Antiprotozoals • Anthelmintics
Malignant and Immune disease (L)Anticancer agents • Immunosuppressants
Muscles, Bones, and Joints (M)Anabolic steroids • Anti-inflammatories • Antirheumatics • Corticosteroids • Muscle relaxants
Brain and Nervous system (N)Anesthetics • Analgesics • Anticonvulsants • Mood stabilizers • Anxiolytics • Antipsychotics • Antidepressants • Nervous system stimulants
Respiratory system (R)Bronchodilators • Decongestants • Antihistamines
Drugs for acid related disorders: Antacids (A02A)
MagnesiumMagnesium carbonate - Magnesium oxide - Magnesium peroxide - Magnesium hydroxide - Magnesium silicate
AluminiumAluminium hydroxide - Algeldrate - Aluminium phosphate - Dihydroxialumini sodium carbonate - Aluminium acetoacetate - Aloglutamol - Aluminium glycinate
Calcium Calcium carbonate - Calcium silicate
Lansoprazole
Omeprazole
ANTIVIRAL DRUGS:
Definition
Antiviral drugs are medicines that cure or control virus infections.
Purpose
Antivirals are used to treat infections caused by viruses. Unlike antibacterial drugs, which may cover a wide range of pathogens, antiviral agents tend to be narrow in spectrum, and have limited efficacy.
Description
Antiviral drugs are a class of medication used specifically for treating viral infections. Like antibiotics, specific antivirals are used for specific viruses. Antiviral drugs are one class of antimicrobials, a larger group which also includes antibiotic, antifungal and antiparasitic drugs. They are relatively harmless to the host, and therefore can be used to treat infections. They should be distinguished from viricides, which actively deactivate virus particles outside the body.
The drugs act by interfering with a virus's ability to enter a host cell and replicate itself with the host cell's DNA. Some drugs block the virus's attachment or entry into the cell; others inhibit replication or prevent the virus from shedding the protein coat that surrounds the viral DNA. Antiviral drug development has been concurrent with advances in molecular biology and genetic engineering that allow study and definition of the genetic codes of viral DNA. Study at this level was not possible until electron microscopes became available and it is only since the 1980s that antiviral drugs have been on the market.
Exclusive of the antiretroviral agents used in HIV (AIDS) therapy, there are currently only 11 antiviral drugs available, covering four types of virus. Acyclovir (Zovirax), famciclovir (Famvir), and valacyclovir (Valtrex) are effective against the herpes virus, including herpes zoster and herpes genitalis. They may also be of value in either conditions caused by herpes, such as chicken pox and shingles. These drugs are not curative, but may reduce the pain of a herpes outbreak and shorten the period of viral shedding.
Amantadine (Symmetrel), oseltamivir (Tamiflu), rimantidine (Flumadine), and zanamivir (Relenza) are useful in treatment of the influenza virus. Amantadine, rimantadine, and oseltamivir may be administered throughout the flu season as preventatives for patients who cannot take influenza virus vaccine.
Cidofovir (Vistide), foscarnet (Foscavir), and ganciclovir (Cytovene) have been beneficial in treatment of cytomegalovirus in immunosupressed patients, primarily HIV-positive patients and transplant recipients. Ribavirin (Virazole) is used to treat respiratory syncytial virus. In combination with interferons, ribavirin has shown some efficacy against hepatitis C, and there have been anecdotal reports of utility against other types of viral infections.
As a class, the antivirals are not curative, and must be used either prophylactically or early in the development of an infection. Their mechanism of action is typically to inactivate the enzymes needed for viral replication. This will reduce the rate of viral growth, but will not inactive the virus already present. Antiviral therapy must normally be initiated within 48 hours of the onset of an infection to provide any benefit. Drugs used for influenza may be used throughout the influenza season in high risk patients, or within 48 hours of exposure to a known carrier. Antiherpetic agents should be used at the first signs of an outbreak. Anti-cytomegaloviral drugs must routinely be used as part of a program of secondary prophylaxis (maintenance therapy following an initial response) in order to prevent reinfection in immunocompromised patients.
FOR FLU:
Amantadine-- Symmetrel Oseltamivir-- Tamiflu
Flumadine -- Rimantadine Zanamivir -- Relenza
FOR HERPES:
Acylclovir Tromantadine
1. pertaining to, characterized by, or producing anesthesia. 2. a drug or agent used to abolish the sensation of pain, to achieve adequate muscle relaxation during surgery, to calm fear and allay anxiety.
A substance that causes loss of sensation or consciousness. With the aid of an anesthetic, people can undergo surgery without pain. Agent that produces a local or general loss of sensation, including pain, and therefore is useful in surgery and dentistry. General anesthesia induces loss of consciousness, most often using hydrocarbons (e.g., cyclopropane, ethylene); halogenated (see halogen) hydrocarbons (e.g., chloroform, ethyl chloride, trichloroethylene); ethers (e.g., ethyl ether or vinyl ether); or other compounds, such as tribromoethanol, nitrous oxide, or barbiturates. Local anesthesia induces loss of sensation in one area of the body by blocking nerve conduction (see nervous system, neuron), usually with alkaloids such as cocaine or synthetic substitutes (e.g., lidocaine).
Early modern medical anesthesia dates to experiments with nitrous oxide (laughing gas) by Sir Humphry Davy of England. General anesthetics, administered by inhalation or intravenous injection, cause unconsciousness as well as insensibility to pain, and are used for major surgical procedures. In the past, ether was the most commonly used general anesthetic. Today, safer anesthetics include Halothane and Isoflurane, both of which are administered through inhalation. Short-acting anesthetic agents, such as pentothal, Diprivan, and Midazolam, are generally given through intravenous or intramuscular routes. Inhaled nitrous oxide is used for light anesthesia in minor surgical procedures and in dentistry. Ultra-short-acting analgesics can also be given intranasally for pre-medication prior to the induction of general anesthesia. Anesthetics such as Brevital may be administered rectally, primarily among children.
Local anesthetics affect sensation only in the region where they are injected, and are used regularly in dentistry and minor surgery. Spinal and epidural anesthesia involves the injection of an anesthetic agent into a space adjacent to the spinal cord, a technique frequently employed for surgical procedures below the waist (e.g., obstetrics) where total unconsciousness is not necessary. Such anesthetics are known as regional blocks. Muscle relaxants may be used in conjunction with general anesthetics, particularly to reduce
the amount of anesthetic required. Body temperatures are generally lowered in conjunction with the use of anesthetics in heart and brain surgery, reducing the body's metabolic rate so that cells are not damaged by the lack of circulating blood and reduced oxygenation. Several forms of anesthesia may be used in combination. Safer and more efficient anesthetics are constantly researched, in the hopes of perfecting new ways of combining and administering them.
Novacaine
AN TI-INSOMNIA DRUGS:
Definition
Anti-insomnia drugs are medicines that help people fall asleep or stay asleep.
Description
The anti-insomnia drug described here, zolpidem (Ambien), is a classified as a central nervous system (CNS) depressant. CNS depressants are medicines that slow the nervous system. Physicians also prescribe medicines in the benzodiazepine family, such as flurazepam (Dalmane), quazepam (Doral), triazolam (Halcion), estazolam (ProSom), and temazepam (Restoril), for insomnia. Benzodiazepine drugs are described in the essay on antianxiety drugs. Zaleplon (Sonata) is another anti-insomnia drug that is not related to other drugs with the same effect. The barbiturates, such as pentobarbital (Nembutal) and secobarbital (Seconal) are no longer commonly used to treat insomnia because they are too dangerous if they are taken in overdoses. For patients with mild insomnia, some antihistamines, such as diphenhydramine (Benadryl) or hydroxyzine (Atarax) may be used, since these also cause sleepiness.
Zolpidem is available only with a physician's prescription and comes in tablet form.
Ambien Melatonin
Rozerem
CHEMOTHERAPY DRUGS:
Definition
Chemotherapy is treatment of cancer with anticancer drugs.
Description
More than 50 chemotherapy drugs are currently available to treat cancer and many more are being tested for their ability to destroy cancer cells. Most chemotherapy drugs interfere with the ability of cells to grow or multiply. Although these drugs affect all cells in the body, many useful treatments are most effective against rapidly growing cells. Cancer cells grow more quickly than most other body cells. Other cells that grow fast are cells of the bone marrow that produce blood cells, cells in the stomach and intestines, and cells of the hair follicles. Therefore, the most common side effects of chemotherapy are linked to their effects on other fast growing cells.
Types of chemotherapy drugs
Chemotherapy drugs are classified based on how they work. The main types of chemotherapy drugs are described below:
Alkylating drugs kill cancer cells by directly attacking DNA, the genetic material of the genes. Cyclophosphamide is an alkylating drug.
Antimetabolites interfere with the production of DNA and keep cells from growing and multiplying. An example of an antimetabolite is 5-fluorouracil (5-FU).
Antitumor antibiotics are made from natural substances such as fungi in the soil. They interfere with important cell functions, including production of DNA and cell proteins. Doxorubicin and bleomycin belong to this group of chemotherapy drugs.
Plant alkaloids prevent cells from dividing normally. Vinblastine and vincristine are plant alkaloids obtained from the periwinkle plant.
Steroid hormones slow the growth of some cancers that depend on hormones. For example, tamoxifen is used to treat breast cancers that depend on the hormone estrogen for growth.
Combination chemotherapy
Chemotherapy is usually given in addition to other cancer treatments, such as surgery and radiation therapy. When given with other treatments, it is called adjuvant chemotherapy. An oncologist decides which chemotherapy drug or combination of drugs will work best for each patient. The use of two or more drugs together often works better than a single drug for treating cancer. This is called combination chemotherapy. Scientific studies of different drug combinations help doctors learn which combinations work best for each type of cancer.
Taxol
Cisplatin
SEROTONIN UPTAKE INHIBITORS:
Prozac
Fluoxetine hydrochloride (Prozac) is an antidepressant of the selective serotonin reuptake inhibitor (SSRI) class. Fluoxetine is approved for the treatment of clinical depression (including pediatric depression), obsessive-compulsive disorder (in both adult and pediatric populations), bulimia nervosa, panic disorder and premenstrual dysphoric disorder.[1] Other indications include hypochondriasis and body dysmorphic disorder. Despite the availability of newer agents, it remains extremely popular. Over 23.1 million prescriptions for generic formulations of fluoxetine were filled in the United States in 2006, making it the third most prescribed antidepressant.[2]
CHOLESTROL LOWERING STATINS:
Atorvastatin marketed under the trade name Lipitor and several others, is a member of the drug class known as statins, used for lowering cholesterol. Atorvastatin inhibits the rate-determining enzyme located in hepatic tissue that produces mevalonate, a small molecule used in the synthesis of cholesterol and other mevalonate derivatives. This lowers the amount of cholesterol produced which in turn lowers the total amount of LDL cholesterol. With 2006 sales of US$12.9 billion under the brand name Lipitor, it is the largest selling drug in the world. Lipitor is not the only statin. There are over 5 other statins in the market.
Statins currently available on the U.S. market include: Lipitor (atorvastatin) - Pfizer Zocor (simvastatin) - Merck Pravachol (pravastatin) - Bristol-Myers Squibb Lescol (fluvastatin) - Novartis Mevacor (lovastatin) - Merck Crestor (rosuvastatin) - AstraZeneca.
The statins (or HMG-CoA reductase inhibitors) form a class of hypolipidemic drugs used to lower cholesterol levels in people with or at risk of cardiovascular disease. They lower cholesterol by inhibiting the enzyme HMG-CoA reductase, which is the rate-limiting enzyme of the mevalonate pathway of cholesterol synthesis. Inhibition of this enzyme in the liver stimulates LDL receptors, resulting in an increased clearance of low-density lipoprotein (LDL) from the bloodstream and a decrease in blood cholesterol levels. The first results can be seen after one week of use and the effect is maximal after four to six weeks.
Pharmacology
As with other statins, atorvastatin is a competitive inhibitor of HMG-CoA reductase. Unlike most others, however, it is a completely synthetic compound. HMG-CoA reductase catalyzes the reduction of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) to mevalonate, which is the rate-limiting step in hepatic cholesterol biosynthesis. Inhibition of the enzyme
decreases de novo cholesterol synthesis, increasing expression of low-density lipoprotein receptors (LDL receptors) on hepatocytes. This increases LDL uptake by the hepatocytes, decreasing the amount of LDL-cholesterol in the blood. Like other statins, atorvastatin also reduces blood levels of triglycerides and slightly increases levels of HDL-cholesterol.
In clinical trials, adding ezetimibe (Zetia) to Lipitor lowered cholesterol more effectively than Vytorin (ezetimibe + simvastatin).
Lipitor Provachol
Zocor
COX-2 INHIBITORS:
COX-2 selective inhibitor is a form of Non-steroidal anti-inflammatory drug (NSAID) that directly targets COX-2, an enzyme responsible for inflammation and pain. Selectivity for COX-2 reduces the risk of peptic ulceration, and is the main feature of celecoxib, rofecoxib and other members of this drug class. Cox-2-selectivity does not seem to affect other adverse-effects of NSAIDs (most notably an increased risk of renal failure), and some results have aroused the suspicion that there might be an increase in the risk for heart attack, thrombosis and stroke by a relative increase in thromboxane.
The existing nonsteroidal antiinflammatory drugs (NSAIDs) differ in their relative specificities for COX-2 and COX-1; while aspirin is equipotent at inhibiting COX-2 and COX-1 enzymes in vitro and ibuprofen demonstrates a sevenfold greater inhibition of COX-1, other NSAIDs appear to have partial COX-2 specificity, particularly meloxicam (Mobic).
Although individual reactions to particular NSAIDs vary, in general the efficacy of COX-2 inhibitors has proved similar to that of other NSAIDs, as expected since both classes of drug inhibit the desired target, the action of COX-2 prostaglandins. The drugs's effectiveness is similar to that of traditional NSAIDs such as ibuprofen, diclofenac, or naproxen.
A model comparing the theoretical relative frequency of gastrointestinal adverse effects and cost effectiveness of celecoxib, nonspecific NSAIDs alone, NSAIDs plus a proton pump inhibitor, NSAIDs plus an H2 receptor antagonist, NSAIDs plus misoprostol, and diclofenac/misoprostol, found the lowest probability of adverse gastrointestinal events for celecoxib, followed by NSAIDs plus a proton pump inhibitor, NSAIDs plus an H2 receptor antagonist, NSAID plus misoprostol, diclofenac/misoprostol, and NSAID alone. In total cost, including drug plus treatment of any gastrointestinal effects, the lowest cost treatment was celecoxib, followed by NSAIDs alone and diclofenac/misoprostol, with the other NSAID plus gastrointestinal
protection regimens being much more costly. Similarly, a model of cost effectiveness of rofecoxib and celecoxib compared to high-dose acetaminophen or ibuprofen, with and without misoprostol, in patients with osteoarthritis of the knee found that acetaminophen had the lowest cost for average patients. For those not responding to paracetamol, ibuprofen was the most cost effective treatment by a large margin, but for those who did not respond to acetaminophen and had a high risk of gastrointestinal damage, rofecoxib was the most cost effective treatment.
COX-2 enzyme has an adverse effect on the tumor suppressor, p53. p53 is an apoptosis transcription factor normally found in the cytosol, when cellular DNA is damaged beyond repair, p53 is transported to the nucleus where is promotes p53 mediated cell suicide (apoptosis) (Lau et al, 2006). Two of the metabolites of COX-2, prostaglandin A2 (PGA2) and A1 (PGA1), when present in high quantities binds to p53 in the cytosol and inhibits its ability to cross into the nucleus. This essentially sequesters p53 in the cytosol and prevents apoptosis (Lau et al, 2006). coxibs such as CELEBREX® (celecoxib), by selectively inhibiting the overexpressed COX-2, allow p53 to work properly. Functional p53 allows DNA damaged neuroblastoma cells to commit suicide through apoptosis, halting tumor growth. COX-2 up-regulation has also been linked to the phosphorylation and activation of the E3 ubiquitin ligase HDM2, a protein that mediates p53 ligation and tagged destruction, through ubiquitination (Lau et al, 2006).
Bextra Celebrex
Vioxx
ANTI-IMPOTENCE AGENTS:
Sildenafil citrate, sold under the names Viagra, Revatio and under various other names, is a drug used to treat male erectile dysfunction (impotence) and pulmonary arterial hypertension (PAH), developed by the pharmaceutical company Pfizer. Its primary competitors on the market are tadalafil (Cialis), and vardenafil (Levitra).
Viagra
PARINSON’S DISEASE MANAGEMENT:
Levodopa (INN) or L-DOPA (3,4-dihydroxy-L-phenylalanine) is an intermediate in dopamine biosynthesis. In clinical use, levodopa is administered in the management of Parkinson's disease. It is also used as a component in marine adhesives used by pelagic life. Levodopa has a chemical formula of C9H11NO4
and a molecular weight of 197.19 g/mol.
Therapeutic use
Levodopa is used as a prodrug to increase dopamine levels for the treatment of Parkinson's disease, since it is able to cross the blood-brain barrier, whereas dopamine itself cannot. Once levodopa has entered the central nervous system (CNS), it is metabolized to dopamine by aromatic L-amino acid decarboxylase. Pyridoxal phosphate (vitamin B6) is a required cofactor for this decarboxylation, and may be administered along with levodopa, usually as pyridoxine.
However, conversion to dopamine also occurs in the peripheral tissues, i.e. outside the brain. This causes adverse effects and decreases the available dopamine to the CNS, so it is standard practice to co-administer a peripheral DOPA decarboxylase inhibitor—carbidopa or benserazide—and often a catechol-O-methyl transferase (COMT) inhibitor. In contrast, co-administration of pyridoxine without a decarboxylase inhibitor accelerates the extracerebral decarboxylation to such an extent that it cancels out the effects of levodopa administration, a circumstance which historically caused great confusion.
Idopa