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DRUGS AFFECTING THE CENTRAL NERVOUS

SYSTEMChap. 11, 13, 15, 16, 17

BRAIN AND SPINAL CORD

PRIMARY FUNCTION – CONTROLS AND COORDINATES THE BODY AND BODY SYSTEMS

DRUGS CAN: ALTER BEHAVIOR / CONSCIOUSNESS› BY STIMULATING OR DEPRESSING CNS – FOR

DESIRED AFFECT

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A substance (norepinephrine, acetylcholine, dopamine, or hormone) that is released when the terminal axon of a presynaptic neuron is excited and acts by exciting or inhibiting a target cell.

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DEPRESS CNS ◦ DRUGS CAN CAUSE THE BRAIN TO BE CALM

SLEEP ANESTHESIA COMA DEATH

STIMULATE CNS – DRUGS CAN ◦ STIMULATE RESPIRATIONS◦ KEEP A PATIENT AWAKE◦ DEPRESS APPETITE

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ACUTE V. CHRONIC PAIN

› ACUTE OCCURS QUICKLY, IS SHORT IN DURATION USUALLY CAN BE RESOLVED

› CHRONIC – LONGER LASTING, USUALLY AT LEAST 3 MONTHS IN DURATION

POSSIBLY WILL NOT GO AWAY

PAIN IS THE SIXTH (6th) VITAL SIGN

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CAUSES OF PAIN / DISCOMFORT

◦TRAUMA

◦TISSUE DAMAGE

◦PRESSURE ON TISSUE AND NERVES

◦INFLAMMATION OF TISSUES AND NERVES

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◦ MASSAGE

◦ POSITION CHANGE

◦ BIOFEEDBACK

◦ EXERCISE

◦ NON-OPOID ANALGESICS

◦ ANTIDEPRESSANTS

◦ Opioid ANALGESICS

◦ STEROIDS

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Pain relievers that contain opium, derived from the opium poppy or chemically related to opium

Very strong pain relievers

Very addicting

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codeine sulfate meperidine HCl (Demerol) methadone HCl (Dolophine) morphine sulfate propoxyphene HCl hydromorphone oxycodone fentanyl Many Others

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Bind to an Opioid receptor in the brain

Cause an analgesic response (reduction of pain sensation)

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Main use: to alleviate moderate to severe pain

Often given with adjuvant drugs to assist primary drugs with pain relief◦Muscle relaxant◦Sedative◦Alternate with non-narcotic analgesic

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Opioids’ are also used for:◦Cough center suppression◦Treatment of diarrhea◦Balanced anesthesia

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Known drug allergy Severe asthma

Use with extreme caution if: Respiratory insufficiency Elevated intracranial pressure Morbid obesity Sleep apnea Paralytic ileus

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Euphoria CNS depression

◦ Leads to respiratory depression◦ Most serious adverse effect

Nausea and vomiting Urinary retention Diaphoresis and flushing Pupil constriction (miosis) Constipation Itching

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A common physiologic result of chronic Opioid treatment

Result: larger dose is required to maintain the same level of analgesia

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Physiologic adaptation of the body to the presence of an Opioid

Opioid tolerance and physical dependence are expected with long-term Opioid treatment and should not be confused with psychologic dependence (addiction)

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A pattern of compulsive drug use characterized by a continued craving for an Opioid and the need to use the Opioid for effects other than pain relief

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Misunderstanding of these terms leads to ineffective pain management and contributes to the problem of undertreatment

Physical dependence is seen when the Opioid is abruptly discontinued or when an Opioid antagonist is administered Opioid withdrawal/Opioid abstinence

syndrome

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Reverse the effects of these drugs on pain receptors

Bind to a pain receptor and exert no response

Also known as competitive antagonists

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ANALEPTICS naloxone (Narcan) naltrexone (Revia)

These drugs bind to opiate receptors and prevent a response

Used for complete or partial reversal of Opioid-induced respiratory depression

Regardless of withdrawal symptoms, when a patient experiences severe respiratory depression, an Opioid antagonist should be given.

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ADMINISTER MEDICATION VERY SLOWLY◦ ANTICIPATE PATIENT RESPONSE TO TREATMENT

MONITOR PATIENT VERY CLOSELY◦ VITAL SIGNS, RESPIRATORY RATE, PULSE OX

CONTINUE TO MONITOR CLOSELY◦ ½ LIFE OF NARCAN = 60 – 90 MINUTES◦ ½ LIFE OF MORPHINE = 2 – 4 HOURS

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Symptoms of “Abstinence Syndrome” Pulmonary edema Withdrawal symptoms Nausea Vomiting Agitation Anxiety Confusion Pain

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Oral forms should be taken with food to minimize gastric upset

Ensure safety measures, such as keeping side rails up, to prevent injury

Withhold dose and contact physician if there is a decline in the patient’s condition or if vital signs are abnormal, especially if respiratory rate is less than 10 to 12 breaths/min

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Check dosages carefully

Follow proper administration guidelines for IM injections, including site rotation

Follow proper guidelines for IV administration, including dilution and rate of administration

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Constipation is a common adverse effect and may be prevented with adequate fluid and fiber intake

Instruct patients to follow directions for administration carefully and to keep a record of their pain experience and response to treatments

Patients should be instructed to change positions slowly to prevent possible orthostatic hypotension

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Decreased complaints of pain Decreased severity of pain Increased periods of comfort Improved activities of daily living,

appetite, and sense of well-being Decreased fever (acetaminophen)

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Contact physician immediately if vital signs change, patient’s condition declines, or pain continues

Respiratory depression may be manifested by respiratory rate of less than 10 breaths/min, dyspnea, diminished breath sounds, or shallow breathing

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Opioid agonist Schedule II narcotic Pregnancy Category C Given orally or parenterally Half life 2 – 4 hours Used for severe pain (chronic or acute)

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Indications Relief of severe/acute/chronic pain, analgesia during labor.

Morphine is the drug of choice for pain due to Myocardial Infarction, dyspnea from pulmonary edema not resulting from chemical respiratory irritant.

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Contraindications Severe respiratory depression, acute/severe asthma, severe hepatic/renal impairment. Used with extreme caution in COPD, hypoxia, head injury, increased intracranial pressure

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Drug-Drug Interactions◦Use with EXTREME CAUTION in patients taking

MAOIs

◦ Increased CNS depression and hypotension with alcohol, sedatives, hypnotics, barbiturates, tricyclic antidepressants, antihistamines

◦May INCREASE the anticoagulant effect of Warfarin (Coumadin)

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› CNS

Impaired judgment

Drowsiness (decrease in LOC)

Decrease in respiratory effort

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Gastrointestinal◦ Dry mouth

◦ Nausea, vomiting

◦Decreased intestinal peristalsis

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CARDIOVASCULAR (CV)

› Bradycardia

› Vasodilation

› Tachycardia

› Flushing

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GENITOURINARY◦ URINARY RETENTION

ALLERGIC◦ RASH◦ ITCHING

RESPIRATORY◦ RESPIRATORY DEPRESSION

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Concurrent use of: Kava kave Valerian root Camomile

◦Can result in increased CNS depression

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IV

PO

IM

IN (intra-nasal)

SC (SQ)

TRANSDERMAL

EPIDURAL

RECTAL

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INTRAVENOUS› Effective within 5 – 10 min. Of administration

› Most common route (in hospitalized patients)

› Frequently administered as patient controlled analgesia (PCA)

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DOUBLE LOCK SYSTEM› TIME› AMOUNT

NURSE MUST DOCUMENT:

› AMOUNT USED

› EFFECTIVENESS

› VITAL SIGNS INCLUDING RESPIRATIONS

› ANY UNTOWARD EFFECTS

› TEACH FAMILY ABOUT USE AND ABUSE

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Catheter is placed into the epidural space to inject a narcotic or anesthetic drug

◦ Obstetrics◦ Surgical procedures◦ Pain management

Catheter may be left in for follow up injections by physician or patient controlled analgesia

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SEVERE PAIN – CHRONIC PAIN› FENTANYL PATCH (DURAGESIC) MOST COMMON

Slower onset but more consistent pain relief Patch usually changed every 72h Treated just as any other narcotic – must account for

every patch Patch must be dated, timed and signed when placed Old patch must be removed when the new one is

placed

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Assess effectiveness of medication◦Use the 0 – 10 scale to measure intensity of

pain

Assess for adverse effects◦Assess rate, depth, and rhythm of

RESPIRATIONS

Provide for patient safety

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Blocks acetylcholine at the neuro-muscular junction

Produces paralysis Does NOT effect LOC Drugs include:

◦ Pancuronium◦ Succinycholine◦ Vecuronium

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Used for uncomfortable procedures such as:◦ Colonoscopy◦ Endoscopy◦ X-ray procedures ◦ Minor surgery

Patient is unconscious but still able to protect their airway

Amnesia is commonmidazolam (Versed) lorazepam (Ativan)

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Chapter 13CNS depressants and

muscle relaxants

Sedative effect:◦Given during waking hours

May cause drowsiness

Hypnotic effect:◦Given at bedtime with the purpose of inducing

sleep

MAY BE THE SAME DRUG GIVEN AT DIFFERENT DOSAGES

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Prototype › Diazepam (Valium)

Antianxiety, anticonvulsant, sedative/hypnotic, skeletal muscle relaxant

Schedule IV drugs – Moderate potential for abuse Pregnancy category D

Half-life 20-50 hours (metabolites also cause sedation up to 100 hours)

Drug of choice to treat status epilepticus (sustained seizures)

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alprazolam (Xanax) chlordiazepoxide (Librium) flurazepam (Dalmane) lorazepam (Ativan) midazolam (Versed) triazolam (Halcion)

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MECHANISM OF ACTION◦Binds with benzodiazepine receptors in nerve

cells of the brain; these cells also have binding sites for GABA (gamma-aminobutyric acid) which is an inhibitory neurotransmitter.

Excitatory v. Inhibitory transmitters◦ Excitatory – Norepinephrine◦ Inhibitory - GABA

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Benzodiazapines and barbiturates work by increasing the action of gaba in the brain

Gaba is an amino acid that inhibits nerve transmissions in the brain

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Indications – Not all drugs are appropriate for all uses◦Antianxiety◦Hypnotic◦Anticonvulsant◦Preoperative sedation◦Prevent DTs in alcohol withdrawal

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Contraindications◦Respiratory depression◦Liver disorder◦Kidney disorder◦History of alcohol or drug abuse◦Used cautiously with other CNS

depressants

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Drug-Drug interactions◦ Cimetidine, hormonal contraceptives, disulfiram,

fluoxetine, isoniazid, ketoconazole, metoprolol, propoxyohene, propranolol, and valproic acid may enhance the effects of sedatives by decreasing their metabolism.

◦ May decrease the efficacy of levodopa

◦ Rifampin, barbiturates may increase the metabolism of benzodiazepines, decreasing their effectiveness.

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Herbal products to avoid when using benzodiazepines◦Kava kava◦Valerian root◦Camomile

CAN INCREASE SEDATION

THIS APPLIES TO ALL CNS DEPRESSANTS

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Adverse Effects

◦CNS depression – drowsiness, lightheadedness

◦Paradoxical effects – insomnia, excitation◦Respiratory depression◦Hypotension◦Constipation/diarrhea◦Nausea, vomiting◦Rash

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REVERSAL AGENT FOR OVERDOSE OF BENZODIAZEPINES:

FLUMAZENIL◦ INDICATED FOR THE REVERSAL OF MODERATE

SEDATION OR GENERAL ANESTHIA

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ASSESS PATIENT WITH FOCUS ON REASON FOR GIVING SEDATION› ANXIETY› NERVOUSNESS

REASSESS PATIENT FOR RESPONSE TO DRUG› SEDATIVE Q 4-6 H› HYPNOTIC AT BEDTIME

MONITOR VS AND POTENTIAL FOR DEPRESSION

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Patient with a history or current use of recreational drugs or alcohol abuse

Respiratory compromise

Pregnancy or lactation

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Administer accurately◦ Teach patient about expected effects and

possible side effects◦ Provide for patient safety

Observe for therapeutic effects◦ Decrease in anxiety◦ Positive signs of sleep

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Observe for adverse effects◦Excessive sedation◦Hypotension

Observe for drug interactions◦Concurrent use of other cns depressants

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ALCOHOL

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Stimulant and depressant◦ Stimulates the adrenal gland◦ Depresses the CNS

Physical manifestations◦ Acts as a diuretic◦ Increases gastric acidity◦ Cardiomyopathy◦ Peripheral vasodilation◦ Electrolyte imbalance

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Delirium tremens – Latin for “shaking frenzy”

Abrupt alcohol (ETOH) withdrawal

Mismatch between excitatory (norepinephrine) and inhibitory (GABA) receptors in the brain

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◦Confusion◦Diarrhea◦Insomnia◦Disorientation◦Agitation◦Fever◦Tachycardia◦Hypertension◦Visions of insects◦Severe anxiety◦Fear of death

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Many safety issues

Do not mix with other CNS depressants

Monitor patients’ liver function

Patient may have altered clotting factors

Patient may have withdrawal symptoms

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PSYCHOTHERAPEUTIC MEDICATIONS

A group of mental disorders characterized by a vague uneasy feeling of discomfort or dread. The symptoms of anxiety prevent the individual from normal functioning . can be an exaggerated response to an actual event or anxiety unrelated to an identifiable event or condition.

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◦Panic disorder◦Generalized anxiety disorder◦Obsessive-compulsive disorder◦Post-traumatic stress disorder◦Simple phobia◦Social phobia

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Tricyclic antidepressants Benzodiazepines MAOIs Buspirone SSRIs

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Mechanism of action – unknown◦Interacts with serotonin and dopamine in

the brain◦No muscle relaxant effects◦No anticonvulsant effects◦Does not cause sedation

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Uses / indications◦Short term management of anxiety disorders◦Not appropriate for immediate relief – may take

several weeks to see effects

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Side effects◦Dizziness, nausea, headache, anxiety,

fatigue, insomnia

Contraindications◦Renal/hepatic failure◦Use of MAOIs

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ANTIDEPRESSANTS AND MOOD STABILIZERS

DRUGS

Monoamine neurotransmitter dysfunction

◦Deficiency of norepinephrine and/or serotonin.◦Balance, integration and interactions among

norepinephrine, serotonin, and other neurotransmission systems is an important etiological factors.

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Neuroendocrine factors

◦AN INCREASE IN CRF (corticotropin releasing factor/hormone) HAS BEEN NOTED IN PATIENTS WITH DEPRESSION.

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Tricyclic antidepressants

Monoamine oxidase inhibitors

Selective serotonin reuptake inhibitors

Unclassified drugs

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imipramine (Tofranil) prototype

nortriptyline (Pamelor) amitryptyline (Elavil) desipramine (Norpramin)

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First generation of antidepressant therapy Mechanism of action

› Corrects the imbalance in the neurotransmitter concentrations of serotonin and norepinephrine at the nerve endings in the CNS. This is done by blocking the reuptake of the neurotransmitters and thus causing these neurotransmitters to accumulate at the nerve

endings.› Also have nonselective receptor antagonism causing

many side effects.

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Indications◦Depression◦Childhood enuresis(bed wetting) Imipramine

◦Obsessive compulsive disorder Clomipramine

◦Chronic pain syndromes Neuropathic pain (trigeminal neuralgia)

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Adverse effects◦Sedation◦Impotence◦Orthostatic hypotension◦Disturbs cardiac conduction◦Delayed micturation◦Edema◦Muscle tremors

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Interactions◦ WHEN TAKEN WITH MAOIs MAY RESULT IN

INCREASED THERAPEUTIC LEADING TO TOXIC EFFECTS (HYPERPYRETIC CRISIS)

◦TCAs can inhibit the metabolism of warfarin, resulting in an increase in anticoagulation

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Toxicity and management of overdose

◦ TCA overdoses are fatal 70% - 80% of the time

◦ Death usually results from seizures or dysrhythmias

◦ THERE IS NO SPECIFIC ANTIDOTE FOR TCAs

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First generation of antidepressant drugs

◦Highly effective◦Many side effects and drug/drug, drug/food

interactions◦Disadvantage: potential to cause hypertensive

crisis when taken with tyramine

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phenelzine (Nardil) tranylcypromine (Parnate)

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Inhibit the MAO enzyme system in the CNS

Amines (dopamine, serotonin, norepinephrine) are

not broken down, resulting in higher levels in the

brain

Result: alleviation of symptoms of depression

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Depression, especially types characterized by

symptoms such as increased sleep and appetite

depression that does not respond to other drugs

such as tricyclics

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Palpitations Drowsiness Headache Nausea Impotence

Tachycardia Dizziness Insomnia Anorexia Blurred vision

Symptoms appear 12 hours after ingestion

Tachycardia, circulatory collapse, seizures, coma

Treatment: protect brain and heart, eliminate toxin

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Ingestion of foods and/or drinks with the amino acid tyramine leads to hypertensive crisis, which may lead to cerebral hemorrhage, stroke, coma, or death

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Avoid foods that contain tyramine!

Aged, mature cheeses (cheddar, blue, Swiss) Smoked/pickled or aged meats, fish, poultry (herring,

sausage, corned beef, salami, pepperoni, pâté) Yeast extracts Red wines (Chianti, burgundy, sherry, vermouth) Italian broad beans (fava beans)

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Concurrent use of MAOIs and SSRIs may lead to serotonin syndrome

If the decision is made to switch to an SSRI, there must be a 2- to 5-week “wash-out” period between MAOI therapy and SSRI therapy

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Delirium AgitationTachycardia SweatingHyper-reflexia Muscle spasmsShivering Coarse tremors

More severe cases

Hyperthermia SeizuresRenal failure DIC

RhabdomyolysisDysrhythmias

fluoxetine (Prozac)paroxetine (Paxil)sertraline (Zoloft)fluvoxamine (Luvox)citalopram (Celexa)escitalopram (Lexapro)

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Fewer adverse effects than tricyclics and

MAOIs

Very few drug-drug or drug-food interactions

Still takes about 4 to 6 weeks to reach

maximum clinical effectiveness

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Mechanism of action Selectively inhibits serotonin reuptake Little or no effect on norepinephrine or dopamine

reuptake Result in increased serotonin concentrations at

nerve endings

Advantage over tricyclics and MAOIs: little or no effect on cardiovascular system

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INDICATIONS

◦Depression

◦Bipolar disorder

◦Obesity

◦Eating disorders

◦Obsessive-compulsive disorder

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Body System Effects CNS Headache, dizziness,

tremor, nervousness, insomnia,* fatigue

GI Nausea, diarrhea,constipation, dry mouth

Other Sexual dysfunction, * weight gain,* weightloss, sweating

* Most common and bothersome

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Duloxetine (Cymbalta) Venlafaxine (Effexor)

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Indicated ◦ For depression and general anxiety disorder◦ Also pain associated with diabetic peripheral

neuropathy

Contraindicated◦ CONCURRENT USE OF MAOIs◦ Angle closure glaucoma

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Drug Interactions◦Highly bound to plasma proteins◦Compete with other protein-binding

drugs, resulting in more free, unbound drug to cause a more pronounced drug effect

◦Inhibition of cytochrome P-450 system

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bupropion◦ Wellbutrin, zyban

Commonly prescribed for smoking cessation maprotiline

◦ Similar to TCAs Mirtazapine

◦ Remeron Often prescribed to enhance appetite

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Comprehensive patient history Complete medication history Monitor patient for therapeutic effects Monitor patients for adverse effects Education of patient on drug expectations

and adverse effects Educate patient regarding drug-drug, drug-food

and drug-herbal interactions

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lithium carbonate Eskalith, lithobid

◦ MOA – not completely understood Managed using serum levels

◦ Indications – mania, bipolar disorder◦ Adverse effects

vomiting, diarrhea, drowsiness, difficult coordination, hand tremors, muscle twitching, mental confusion

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Monitor serum lithium levels◦ Therapeutic levels are 1.0 – 1.5 meq/L

Lithium is eliminated intact by the kidneys. Encourage fluids to completely eliminate the drug

Monitor for therapeutic and adverse effects

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A severe mental disorder characterized by disordered thought process and often bizarre thinking.

Hypoactivity or hyperactivity Agitation Aggressiveness Hostility Social withdrawal

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Antipsychotic AKA Neuroleptic:

◦Any drug that modifies or treats psychotic behaviors usually by blocking dopamine receptors in the brain

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Thioxanthenesthiothixene (Navane)

Phenylbutylpiperidineshaloperidol (Haldol)

Dihydroindolonesmolindone (Moban)

Dibenzodiazepinesloxapine (Loxitane)

BenisoxazolesRisperidone

QuinolinineAripiprazole (Abilify)

PhenothiazinesChlorpromazine (Thorazine)

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Schizophrenia◦ Long half-life facilitates better compliance

by patients

Long-term treatment of psychosis

Can be given either IV or po

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Seizures

Extrapyramidal reactions

Blurred vision, dry eyes

Neuroleptic malignant syndrome

Tartive dyskinesia

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A potentially fatal syndrome with symptoms:◦ Hyperthermia◦ Catatonic rigidity◦ Altered mental status◦ Profuse sweating◦ Rhabdomyolysis◦ Renal failure◦ Seizures◦ Death

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◦Involuntary contractions of oral and facial muscles

◦Choreoathetosis (wavelike movements of extremities)

◦Occurs with continuous long-term antipsychotic therapy (esp. phenothiazines)

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◦Involuntary muscle symptoms similar to those of Parkinson’s disease

◦Akathisia (distressing muscle restlessness)

◦Acute dystonia (painful muscle spasms)◦Treated with benztropine (Cogentin) and

trihexyphenidyl (Artane)

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Recognizing extrapyramidal symptoms

http://www.youtube.com/watch?v=WAg2iLEWVh0&playnext=1&list=PLFA09E8C6FCF4EC70&feature=results_main

clozapine (Clozaril) risperidone (Risperdal) olanzapine (Zyprexa) quetiapine (Seroquel) ziprasidone (Geodon) aripiprazole (Abilify)

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Block dopamine receptors in the brain (limbic system, basal ganglia)—areas associated with emotion, cognitive function, motor function

Dopamine levels in the CNS are decreased

Result: tranquilizing effect in psychotic patients

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◦Reduced effect on Prolactin levels Stimulates mammary glands to produce milk

◦Lower risk of Neuroleptic malignant syndrome Extrapyramidal adverse effects Tartive dyskinesia

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Treatment of serious mental illnesses◦ Bipolar affective disorder◦ Depressive and drug-induced psychoses◦ Schizophrenia◦ Autism

Movement disorders (such as Tourette’s syndrome)

Some medical conditions◦ Nausea, intractable hiccups

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Body System Adverse EffectsCNS Sedation, deliriumCardiovascular Orthostatic hypotension,

syncope, dizziness, EKG changes

Dermatologic Photosensitivity, skin rash, hyper-pigmentation, pruritus

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Body System Adverse Effects

GI Dry mouth, constipation

GU Urinary hesitancy or retention, impaired erection

Hematologic Leukopenia andagranulocytosis

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Body System Adverse Effects

Metabolic/endocrine Galactorrhea, irregular menses,increased appetite,

polydipsia

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Before beginning therapy, assess both the physical and emotional status of patients

Obtain baseline vital signs, including postural BP readings

Obtain liver and renal function tests

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Assess for possible contraindications to therapy, cautious use, and potential drug interactions

Assess LOC, mental alertness, potential for injury to self and others

Check the patient’s mouth to make sure oral doses are swallowed

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Provide simple explanations about the drug, its effects, and the length of time before therapeutic effects can be expected

Abrupt withdrawal should be avoided

Advise patients to change positions slowly to avoid postural hypotension and possible injury

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The combination of drug therapy and psychotherapy is emphasized because patients need to learn and acquire more effective coping skills

Only small amounts of medications should be dispensed at a time to minimize the risk of suicide attempts

Simultaneous use of these drugs with alcohol or other CNS depressants can be fatal

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Skeletal muscle relaxants are used to decrease muscle spasm or spasticity that occurs in certain neurologic and musculoskeletal disorders.

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Indications

› Relief of painful musculoskeletal conditions Muscle spasms Management of spasticity of severe

chronic disorders Multiple sclerosis, cerebral palsy

› Work best when used along with physical therapy

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Muscle spasms◦Sudden involuntary muscle contraction

◦Can occur secondary to trauma, inflammation, sprains, strains, arthritis, spinal disorders

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MECHANISM OF ACTION Act to relieve pain associated with skeletal

muscle spasms Majority are central acting

◦ CNS is the site of action◦ Similar in structure and action to other CNS

depressants Direct acting

◦ Acts directly on skeletal muscle◦ Closely resembles GABA (an inhibitory

neurotransmitter)

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baclofen (Lioresal) cyclobenzaprine (Flexeril) carisoprodol (Soma) metaxalone (Skelaxin) methocarbamol (Robaxin) tizanidine (Zanaflex) DIRECT ACTING

dantrolene (Dantrium)

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Muscle spasticity◦Spasticity involves increased muscle tone or

contraction

◦Can occur secondary to spinal cord injury, multiple sclerosis, cerebral palsy, muscular dystrophy

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Extension of effects on CNS and skeletal muscles◦Euphoria◦Lightheadedness◦Dizziness◦Drowsiness◦Fatigue◦Muscle weakness, others

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Nursing implications◦Monitor therapeutic response to medication◦Monitor for adverse reactions◦Nursing diagnosis appropriate to specific

patient

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AnticonvulsantsAntiseizure drugs

Antiepileptic drugs (AEDs)

Chapter 15MEDICATION TO

CONTROL SEIZURES

A brief episode of abnormal electrical activity of nerve cells in the brain

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GOAL OF TREATMENT◦Control seizures without causing undue sedation

and experiencing minimal adverse reactions

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CARBAMAZAPINE

TEGRETOLCLONAZEPAM

KLONOPINCHLORAZEPATE

TRANXENEDIAZEPAM

VALIUMPHENOBARBITAL

LUMINAL

FOSPHENYTOINCEREBYX

GABAPENTINNEURONTIN

LORAZEPAMATIVAN

PHENYTOIN (PROTOTYPE)

DILANTINVALPROIC ACID

DEPAKENE

DRUGS TO CONTROL SEIZURES

FIRST USED IN 1903› PHENOBARBITAL

MOST COMMONLY PRESCRIBED FOR STATUS EPILEPTICUS

MORE OFTEN USED IN NONINDUSTRIALIZED COUNTRIES BECAUSE OF LOW COST

CLINICAL CLASSIFICATION – ANTICONVULSANT, HYPNOTIC

LONG HALF-LIFE

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Classification◦Anticonvulsant◦Antiarrhythmic

MOA ◦Stabilize neuronal membranes in the motor

cortex of the brain. Limits the spread of seizure activity

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Contraindications› Seizures caused by hypoglycemia or high fever

Side effects› Drowsiness, lethargy, confusion, slurred speech› Gingival hyperplasia› Fever, rash, lymphadenopathy

Monitor serum dilantin levels› 10 -20 mcg/ml IS THERAPEUTIC

Monitor liver function Decreases many drug levels including oral

contraceptives

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NURSING CONSIDERATIONS◦ REVIEW HISTORY OF SEIZURES◦ INITIATE SEIZURE PRECAUTIONS

◦ PATIENT EDUCATION WHAT TO EXPECT FROM MEDICATION DO NOT EVER OMIT A DOSE MUST MAINTAIN THERAPEUTIC BLOOD LEVELS OR

SEIZURES WILL RECUR

◦ SEE “NURSING PROCESS – ASSESSMENT” P.238

◦ DOCUMENT TYPE AND CHARACTER OF SEIZURE

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Classification:◦Anticonvulsant◦Vascular headache suppressant

Mechanism of action◦Increases levels of gaba in the CNS

Adverse reactions

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Adverse reactions Agitation Dizziness Headache Insomnia Sedation Visual disturbances Tremor Ataxia

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Classification – anticonvulsant

Mechanism of action ◦ Alters ion transport in the CNS

Indicated for short term management of generalized seizures, status epilepticus

Parenteral administration only

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Indications – treatment of clonic-tonic, mixed and complex seizures

Mechanism of action – decreases synaptic transmission in the CNS by affecting sodium channels in the neurons

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Adverse reactions Ataxia Drowsiness

Drug-drug interactions◦ Many

Drug food interactions◦ Grapefruit juice increases serum levels and increases

the drug effects (toxicity?)

THERAPEUTIC SERUM DRUG LEVELS – 4-12mcg/ml

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DRUGS FOR PARKINSON’S

DISEASE

Progressive, degenerative neurologic disorder caused by a imbalance between acetylcholine and dopamine in the brain

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Signs and symptoms

› Shuffling gait

› Fine tremors

› Muscle rigidity

› Slurred speech

› Emotionless facial expression (mask-like)

› Difficulty chewing and swallowing

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Anticholinergic drugs

Antihistamines

Dopaminergic’s

◦ Direct acting dopamine receptor agonists

◦ Indirect acting dopamine receptor agonists

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benztropine, procyclidine, trihexyphenidyl

◦Drugs that block the effects of acetylcholine As dopamine decreases, acetylcholine

increases causing muscle tremors and rigidity (more pronounced at rest) Pill rolling

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Anticholinergic effects DECREASE:◦Salivation◦Tearing of the eyes, ◦Urination◦Diarrhea◦Increased GI motility◦Emesis (vomiting)

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Contraindications◦Known drug allergy◦GI or bladder obstruction◦Cardiac disease◦Glaucoma◦Myasthenia gravis

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Used for their anticholinergic effects

◦ diphenhydramine (Benadryl)

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Direct acting medication increase the levels of dopamine at the synapse.

› bromocriptine – dopamine agonist› pergolide – dopamine agonist› pramipexole - dopamine agonist› levodopa – dopamine replacement

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Indirect acting increase dopamine levels by inhibiting enzymes that break down dopamine

› Carbidopa – inhibits enzyme AADC› Entacapone – COMT inhibitor› Tolcapone – COMT inhibitor› Selegiline – MAOI

Others› Amantadine – synthetic antiviral

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Levodopa (prototype)◦ Precursor to dopamine

Dopamine does not cross the blood-brain barrier. Can cross as levodopa and is then converted to dopamine

Carbidopa◦ Prevents the conversion of levodopa to dopamine in

the peripheral tissues◦ Does not cross the blood brain barrier

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ACTION OF MAO◦ Primary roll is the catabolism or breakdown of

catecholamines such as dopamine, norepinephrine and epinephrine. Also breaks down serotonin.

Rasagiline (azilect)

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Catechol-o-methytransferase

◦A naturally occurring enzyme in the body that breaks down dopamine molecules

◦By inhibiting this enzyme, the action of levodopa is prolonged

◦Medications: tolcapone (Tasmar) entacapone (Comtan)

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Drowsiness

Confusion

Orthostatic hypotension

Dystonia

Dyskinesia

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Risk for injury due to postural hypotension

◦ Rise slowly from sitting or lying position

Difficulty with communication

Safety issues r/t unsteady, shuffling gait

Never stop meds abruptly

Take meds on time

Watch for adverse reactions

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ON – OFF: Disease is worsening, too little dopamine is present

WEARING OFF: Gradual worsening of Parkinson’s symptoms as the drugs lose their effectiveness

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