Pharmacology for Biotech

Information taken from Healthcare Science Technology

“The difference between a deadly poison and life saving medicine can be very small; In fact, it is sometimes merely a question of dosage.” Dr. R.E. Schultes

Pharmacology

The study of chemical agents and living organisms and all aspects of their interactions i.e. biological response

Xenobiotics: drug substances foreign to the body such as pollutants, food additives, and drugs

Pharmacokinetics

Pharmacokinetics is the study of the five processes that affect the plasma concentration of drugs. (ADMET)

Pharmacokinetics (cont.)

Absorption – the process by which a drug enters the plasma. Oral medications are dissolved in the

stomach. Can be absorbed thru lungs, skin, or

the GI tract

Pharmacokinetics (cont.)

Distribution – where the drug goes after entering the plasma. Some of the drug binds to the proteins in the

plasma; some diffuses into other tissues. Liberation: the process of drug “release” from

dosage form

Metabolic transformation – chemical changes in a drug that occur after it has been absorbed into the body.

Pharmacokinetics (cont.)

Elimination or excretion – the process that removes a drug from the body. Excreted via skin, lungs, kidneys, intestines

Toxicology – the study of poisons and the toxicity of drugs to the body Worry about toxicity if on an antibiotic too long A negative concern about taking drugs especially if

you will be on them a long time

Routes of Administration

Routes of Administration (ROA) – the different ways used to get a drug into the tissues of the body.

Routes of Administration (cont.) Oral Administration

The most common route. Client swallows a tablet, capsule, or liquid.

Usually requires 30 to 60 minutes before producing an effect, or onset of action.

Analgesics: drugs to reduce pain such as Tylenol as OTC or vicodin or morphine which are much stronger and need Rx

Routes of Administration (cont.) Parenteral Administration – all forms of administration, other than oral. Metered-Dose Inhaler

Delivers medications directly to the lungs.

Rapid action. Minimal systemic side

effects. Nasal spray, suppository,

drops

Routes of Administration (cont.) Transdermal Patch –

one of the most consistent and convenient dosage forms. Remove and discard

old patch. Select a site for new

patch. Apply the patch.

Topical ointments

Hormone therapies, nicotine patches

Often times this is an anti-itch

Routes of Administration (cont.) Injections – used when a rapid effect is needed.

Intravenous (IV) injection – into the vein Subcutaneous (SC) injection – most frequently

given in the upper arm, front of thigh, or abdomen.

Intramuscular (IM) injection – normally given into relatively large muscles of the shoulder, buttocks, or outer portions of the thigh.

Take your best guess!

What is the largest volume that can be given with an SC injection?

Answer:

The largest volume is 1 milliliter (mL).

Dosages

Dosages are usually based on the weight of an individual.

Dosages (cont.)

Effects of Individual Differences on Maintenance Doses Age, body fat, and diseases that

affect the liver and kidneys may require altering the dosage of a drug.

Apply Your Knowledge

List the 5 processes of pharmacokinetics.

Answer:

1. Absorption

2. Distribution

3. Metabolism

4. Elimination or excretion

5. Toxicology

Systems affected by Drugs!

Nervous system Cardiovascular system Gastrointestinal system Endocrine system

What diseases / drugs effect each system Endocrine System

Hormone treatments for diseases such as Thyroid disease, human growth hormone levels, etc.

Cardiovascular Heart disease: Digitalis Atherosclerosis / high BP: Lipitor and diuretics

(cause kidneys to excrete more water and salt)

What diseases / drugs effect each system Nervous System

Bells Palsy, Cerebral palsy Parkinson’s or Alzheimer’s disease Most nervous disorders are not treated with drugs

Gastrointestinal System Ulcers: Pepcid, Zantac Colon cancer, cirrhosis, hepatitis Diabetes: insulin

How drugs work Receptors – proteins found inside or outside

the cell; bind to Ligands

Ligands – molecules that bind to receptors i.e. hormones or neurotransmitters Types of Ligands

Agonists – activate receptors Antagonists – de-activate receptors by inhibiting the

binding of agonists Inverse agonists – reduce cellular activities

How drugs work (cont.)

Enzymes – proteins that speed up a chemical reaction

Enzyme inhibitors – bind to enzymes and decrease activity i.e. herbicides

Enzyme activators – bind to enzymes and increase activity

Enzyme inhibitor – block substrate from entering enzyme active site or from catalyzing the reaction, can alter amino acid structure

Sources of Drugs

Natural Sources Pharmacognosy is the study of drugs

made from natural sources, such as plants and animals.

Plants were the main source of medicine until the early 1900s, when Sir F. G. Banting and Charles Herbert Best extracted insulin from a pancreas and tested it on diabetic dogs.

Sources of Drugs (cont.)

Natural Sources (cont.) Problems associated with naturally occurring

drugs: Some are broken down very quickly by the

body. Some are poorly absorbed into the

bloodstream. Isolating a drug from a plant or animal can be

slow, expensive, and may result in harmful impurities in the drug.

Naturally occurring products can be extremely scarce.

Sources of Drugs (cont.)

Microbial organisms Penicillin, isolated by Sir Alexander

Fleming in 1928, was one of the first drugs that did not come from a plant or animal.

Large scale manufacture in what year? 1943

Sources of Drugs (cont.) Synthetics and Bioengineering

Medicinal chemistry modifies natural products by producing them synthetically or by creating new products.

Aspirin, synthetically produced today, was once an extract of willow bark.

Insulin was the first drug to be produced from genetically altered bacteria (recombinant)

Sources of Drugs (cont.) Natural Sources (cont.)

Genetically modified E-coli used to make insulin

Bacterial Chromosome

Plasmid containing human insulin gene

Plasmid has been inserted into the bacterial cell

Cell A Cell B

Pharmacotherapeutics

Examines the mechanism of action (MOA) of drugs.

Describes the effects produced by a drug.

Determines what dose of a drug is needed to produce a desired effect.

Determines what dose of a drug produces toxic effects.

Pharmacotherapeutics (cont.)

Mechanisms of Action (MOA) Drugs with the same MOA are said to

belong to the same therapeutic class. Binding occurs when a drug combines with

a chemical in the body. MOA operates on a “lock and key”

principle. The drug is considered the key and the body chemical the lock.

Pharmacotherapeutics (cont.)

Mechanisms of Action (cont.) Binding to and Stimulating a Receptor in the

Body Receptors – proteins found in cells.

Click for Picture

Mechanisms of Action (cont.) Binding to and Blocking a Receptor in the

Body Some drugs, called antagonists or

blockers, bind to a receptor without causing a response, thus preventing the naturally occurring key from binding.

Pharmacotherapeutics (cont.)

Click for Picture

Pharmacotherapeutics (cont.) Mechanisms of Action (cont.)

Inhibiting an Enzyme Enzyme inhibitors increase or decrease the

concentration of an enzyme.

Click for Picture

Pharmacotherapeutics (cont.)

A side effect is any effect produced by a drug that is not the desired effect. Local Side Effects

Occur before a drug is absorbed into the bloodstream.

Pharmacotherapeutics (cont.)

Systemic Side Effects Take place after being absorbed

into the bloodstream. May take the form of an allergic

reaction, since drugs are not a “natural” part of our body.

Most occur because the drug affects cells other than the target cells.

Apply Your Knowledge

Where do drugs come from?

Answer:

1. Natural sources such as plants and animals.

2. Microscopic organisms such as bacteria, fungi, and molds.

3. Synthetics and bioengineering.

Therapeutic Classes of Drugs

Drugs in a therapeutic class produce their effect in the same way.

Examples are listed on the following slides.

Therapeutic Classes of Drugs (cont.) Angiotensin Converting Enzyme Inhibitors

Angiotensin is a naturally occurring protein in the body. An enzyme called angiotension converting enzyme (ACE) activates angiotensin, which, when overactive, causes high blood pressure, or hypertension.

ACE inhibitors reduce the production of angiotensin.

Representative drugs: Accupril®, Lotensin®, Prinivil®, Vasotec®, and Zestril®.

Common side effects include headache and dizziness.

Therapeutic Classes of Drugs (cont.)

Beta-1 Blockers Bind to beta-1 receptors without

stimulating them, preventing epinephrine (adrenalin) and norepinephrine from binding.

Representative drugs: Lopressor®, Tenormin®, Toprol®.

Indications: hypertension, tachycardia or rapid heartbeat.

Common side effects: dizziness, drowsiness.

Therapeutic Classes of Drugs (cont.) Beta-2 Agonists

These drugs bind to beta-2 receptors on the smooth muscle cells of the bronchioles, causing dilation. Representative drugs: Ventolin®, Proventil®, Serevent®, Alupent®, Brethine®.

Indications: asthma, emphysema.

Common side effects: tremors, increased heart rate, and insomnia.

Therapeutic Classes of Drugs (cont.)

Antihistamines Antihistamines bind to histamine

receptors, without stimulating them. Representative drugs: Allegra®,

Benadryl®, Claritin®, Zyrtec®. Indications: itching, nasal

congestion, seasonal allergies such as hay fever.

Common side effects: dry mouth and drowsiness.

Therapeutic Classes of Drugs (cont.)

H2 Antagonists Bind to H2 receptors, found

only in the stomach, to decrease the amount of hydrochloric acid produced.

Representative drugs: Tagamet®, Pepcid®, Zantac®.

Indications: gastroesophageal reflux disorder, gastric ulcers, duodenal ulcers.

Common side effects: diarrhea, headache.

Therapeutic Classes of Drugs (cont.) Proton Pump Inhibitors

Drugs that turn off the proton pumps in the stomach, which reduces stomach acid.

Representative drugs: Prilosec®. Indications: gastroesophageal reflux disorder,

gastric ulcers, duodenal ulcers. Common side effects: diarrhea, headache.

Therapeutic Classes of Drugs (cont.) Narcotic Analgesics

Drugs that bind to and stimulate the endorphin receptors in the spine which inhibit nerve cells that carry pain to the brain.

Representative drugs: morphine, codeine, Demerol®, Vicodin®, Percodan®.

Indications: severe pain. Common side effects: drowsiness, slow and

shallow breathing, constipation.

Therapeutic Classes of Drugs (cont.) Nonsteroidal Anti-inflammatory Drugs

Nonsteroidal anti-inflammatory drugs (NSAIDS) inhibit the enzyme prostaglandin synthase, which makes prostaglandins.

Representative drugs: aspirin, Motrin®, Advil®, Relafen®, Naprosyn®, Aleve®.

Indications: mild to moderate pain, inflammation, fever.

Common side effects: stomach irritation.

Therapeutic Classes of Drugs (cont.) Reverse Transcriptase Inhibitors

Inhibit the activity of the enzyme reverse transcriptase, which is needed to convert RNA to DNA.

Representative drugs: AZT, Combivir®, Sustiva®, Retrovir®.

Indications: HIV infection. Common side effects: anemia, fever, rash, headache,

lack of energy, nausea, vomiting, diarrhea, stomach pain, cough, shortness of breath, sore throat.

Apply Your Knowledge

What type or class of drugs are used to relieve pain? Analgesics such as Tylenol or morphine

What type or class of drugs is given for an allergic reaction Anti histamines

What type or class of drug is given for an ulcer? Proton pump inhibitor such as Prilosec or H2 antagonist such as Zantac