Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Focus on PHARMACOLOGY ESSENTIALS FOR HEALTH PROFESSIONALS CHAPTER 17 Drugs Used to Treat Central Nervous System Conditions Figure 17-1 The central nervous system (CNS) includes the brain and spinal cord. The peripheral nervous system includes the nerves throughout the body that exit from the spinal cord. Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Figure 17-2 The spinal cord. Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini CNS Stimulants: Uses • Diverse group of pharmacologic agents • Exact mechanism of action is not clear but may stimulate cerebral cortex and increase activity of norepinephrine, dopamine, and other catecholamines at CNS synapses. Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini CNS Stimulants: Uses • Indirect-acting sympathomimetics are used to treat attention deficit– hyperactivity disorder (ADHD); very few other therapeutic uses. Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini CNS Stimulants: Adverse Effects • Common: headache, palpitations, cardiac dysrhythmias, hypertension, nervousness, nausea • Highly addictive and widely abused outside therapeutic therapy (especially methamphetamine) Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini CNS Stimulants: Contraindications • Do not use in patients with a history of drug abuse, severe agitation, hyperthyroidism, diabetes mellitus, moderate to severe hypertension, advanced arteriosclerosis, angina pectoris, cardiovascular disorders, or glaucoma. • Safety in pregnancy and lactation not established. Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini CNS Stimulants: Patient Information • Advise patients that taking CNS stimulants for a long time can cause withdrawal symptoms. • Advise families of children with ADHD to seek counseling. Drug therapy alone is insufficient. Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Sedatives and Hypnotics • Sedatives: diminish activity of CNS; used to relieve anxiety • Hypnotics: induce sleep; used for short-term treatment of insomnia • Difference between two drug classes is in the dosage Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Hypnotics and Sleep • No currently available hypnotics induce what can be termed “natural” sleep. Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Table 17-1 Commonly Used Benzodiazepines Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Table 17-1 (continued) Commonly Used Benzodiazepines Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Benzodiazepines: Uses • Mechanism of action appears related to their ability to increase the action of neurotransmitter GABA. • Indicated for generalized anxiety disorders, panic disorders, insomnia, some types of seizures, muscle relaxation Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Benzodiazepines: Adverse Effects • Common: drowsiness, ataxia, impaired judgment, rebound insomnia, tolerance • Serious (with overdosage): CNS and respiratory depression, hypotension, coma Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Benzodiazepines: Contraindications • Do not use in pregnancy, severe liver or kidney disorders, or in hyperactive children. • Interact with alcohol, omeprazole to cause increased CNS depression • Interact with cimetidine, disulfiram, hormonal contraceptives, theophylline, ranitidine Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Benzodiazepines: Patient Information • Educate patients about relaxation techniques and to avoid caffeine, especially close to bedtime. • Advise patients not to abruptly stop medication. • Warn patients to avoid alcohol and other CNS depressants. • Advise patients to avoid driving. Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Oral Contraceptives • Warn women taking benzodiazepines and oral contraceptives that increased sedative effects may occur because high levels of benzodiazepines may accumulate in the blood plasma. Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Barbiturates: Uses • Classified as CNS agents, anticonvulsants, and sedative-hypnotics • May work by inhibiting reticularactivating system, thereby interfering with impulse transmission of cerebral cortex • Used to treat insomnia and for some types of seizures Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Barbiturates: Adverse Effects • Common: sedation, nausea, vomiting, constipation, diarrhea, bradycardia • Serious: respiratory depression, circulatory shock, renal or hepatic damage • Addiction Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Barbiturates: Contraindications • Do not use in patients with familial history of porphyria or with severe respiratory or kidney disease; and in pregnancy or lactation. • Interact with alcohol, oral anticoagulants, corticosteroids, oral contraceptives Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Barbiturates: Patient Information • Instruct patients in relaxation techniques. • Advise patients not to stop the medication suddenly. • Warn patients not to drink alcohol or drive while taking barbiturates. Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Epilepsy • Permanent, recurrent seizure disorder • Seizure: periodic attack of disturbed cerebral function – Generalized tonic-clonic (previously grand mal) – Generalized absence (previous petit mal) – Generalized myoclonic – Partial Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Table 17-2 Most Commonly Prescribed Antiseizure Drugs Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Table 17-2 (continued) Most Commonly Prescribed Antiseizure Drugs Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Table 17-2 (continued) Most Commonly Prescribed Antiseizure Drugs Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Phenytoin (Dilantin): Uses • Most common hydantoin • Reduces voltage, frequency, spread of electrical discharges within motor cortex • Used for partial, tonic-clonic, psychomotor, and nonepileptic seizures Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Phenytoin: Adverse Effects • Common: blurred vision, dizziness, drowsiness, fatigue, thrombocytopenia, aplastic anemias • Excess dosages: confusion, delirium, psychosis Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Phenytoin: Contraindications • Avoid in patients with hypoglycemic seizures, sinus bradycardia, or heart block, and in pregnancy or lactation. • Use cautiously in patients with impaired liver or kidney function, alcoholism, blood disorders, or hypotension. • Lower the dosage in elderly patients. • Numerous drug–drug interactions Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Phenytoin: Patient Information • Advise patients that urine may turn pink or red-brown. • Instruct patients with diabetes to frequently check blood glucose levels. • Advise patients to use good oral hygiene to prevent gingival hyperplasia. Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Valproic Acid (Depakote): Uses • Action may be related to increased bioavailability of GABA to neurons. • Used to treat simple and complex absence seizures • Has been used for other generalized seizures Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Valproic Acid: Adverse Effects • Common: nausea, vomiting, hypersalivation, abdominal cramps, sedation, drowsiness, possible prolonged bleeding time • Serious: liver failure, life-threatening pancreatitis Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Valproic Acid: Contraindications • Safe use during pregnancy not established. • Increases effects of CNS depressants • Interacts with aspirin, warfarin, cimetidine, and other drugs • May alter thyroid function and urine ketone tests Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Valproic Acid: Patient Information • Advise patients to swallow capsules whole or add liquid form to foods or liquids to improve taste. • Instruct patients to take with meals to reduce GI upset. Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Ethosuximide: Uses • Blocks calcium channels to stabilize neuronal excitability, raising threshold of uncontrolled cerebral discharges • Used to control absence and myoclonic seizures and akinetic epilepsy Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Ethosuximide: Adverse Effects • Common: drowsiness, hiccups, ataxia, dizziness, headache, euphoria, restlessness, anxiety, blurred vision, aggressiveness, agranulocytosis, gingival hyperplasia, nausea, vomiting, anorexia • Serious: aplastic anemia Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Ethosuximide: Contraindications • Avoid use in severe liver or kidney disease. • Safety not established in pregnancy, lactation, or children younger than 3 years. • Interacts with primidone, carbamazepine, and isoniazid Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Ethosuximide: Patient Information • Advise patients about possibility of blood disorders. • Instruct patients to report sore throat, fever, or bruising. • Warn patients against driving. Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Carbamazepine (Tegretol): Uses • Promotes sodium efflux, which reduces neuronal excitability, but leaves motor cortex relatively unaffected • Used for partial and tonic-clonic seizures and trigeminal neuralgia • Also used to treat depression and bipolar disorder Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Carbamazepine: Adverse Effects • Common: blood disorders, altered urination, liver or kidney dysfunctions, confusion and agitation in elderly patients especially, blurred vision, dizziness, drowsiness, fatigue • Serious: severe cardiovascular disturbances Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Carbamazepine: Contraindications • Avoid in patients with cardiac or liver impairment. • Use extremely cautiously in pregnancy. • Interacts with antineoplastic agents, antiretroviral protease inhibitors, barbiturates, calcium channel blockers, corticosteroids, and many more drugs Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Carbamazepine: Patient Information • Inform patients that blood disorders may occur. • Advise patients to report sore throat, mucosal ulceration, petechiae, or bruising of unknown cause. Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Parkinson’s Disease • Occurs mostly in elderly individuals • Nervous system disorder characterized by movement abnormalities such as tremor of head and extremities, difficulty coordinating fine muscle movement, hypokinesia (inability or slowness in initiating movements) Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Cause of Parkinson’s Disease • Unknown, but a CNS defect leads to it • Substantia nigra is important to initiation and control of muscular movement • Lack of dopaminergic activity in substantia nigra leads to imbalance between dopamine and acetylcholine Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Figure 17-3 Normal (A) and abnormal (B) balance between dopamine and acetylcholine. Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Parkinsonism • Refers to symptoms produced by certain drugs, poisons, and traumatic lesions in the basal ganglia • Also called secondary parkinsonism • Symptoms may be temporary. Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Treatment of Parkinson’s Disease • No cure available • Drug therapy manages symptoms. • Pharmacotherapy attempts to rebalance dopamine and acetylcholine by: – Decreasing muscarinic activity – Increasing dopaminergic activity by blockings its breakdown or mimicking its action Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Kava • Patients who have Parkinson’s disease should not take the natural product kava, which is often taken as a dietary supplement to reduce stress and anxiety. • Antipsychotics, barbiturates, benzodiazepines, and CNS depressants should not be taken with kava. Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Table 17-3 Anticholinergic Drugs Used for Parkinson’s Disease Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Anticholinergic Drugs: Uses • Work by inhibiting muscarine receptors and blocking effect of acetylcholine • Only centrally acting anticholinergics are used (benztropine and trihexyphenidyl) • Can be used to treat parkinsonism Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Anticholinergics: Adverse Effects • Common: anxiety, agitation, confusion, dry mouth, decreased sweating and heat release • Serious: urticaria, urine retention, paresthesias, sinus tachycardia Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Anticholinergics: Contraindications • Safe use in pregnancy not established. • Should not be given with other antimuscarinics Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Anticholinergics: Patient Information • Instruct patients to avoid alcohol. • Advise patients to consume a high-fiber diet to help ease constipation. • Warn patients to avoid driving because the drug causes drowsiness. Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Table 17-4 Dopaminergic Drugs Used for Parkinson’s Disease Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Table 17-4 (continued) Dopaminergic Drugs Used for Parkinson’s Disease Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Dopaminergics: Uses • Precise mechanism unknown; but dopaminergics are precursors of dopamine • Most commonly used is levodopa (Larodopa) • Used to treat Parkinson’s disease and parkinsonism associated with manganese and carbon monoxide poisoning Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Dopaminergics: Adverse Effects • Common: dyskinesia, hallucinations, mental confusion • Long-term: loss of efficacy • Abrupt discontinuation: neuroleptic malignant syndrome (tachycardia, muscular rigidity, fever, mental status changes, diaphoresis, tachypnea) Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Dopaminergics: Contraindications • Use cautiously in cardiac disease. • Should not be used in patients with a history of allergy to these substances. Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Dopaminergics: Patient Information • Instruct patients to take with food to avoid GI upset and avoid foods rich in vitamin B6 (beans and cereals). • Advise patients to use good oral hygiene. • Warn patients not to discontinue the drug abruptly. Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Schizophrenia • Chronic psychiatric disease • Positive symptoms: exaggerations of normal functioning, such as hallucinations and delusions • Negative symptoms: terse speech, social withdrawal, apathy, anhedonia Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Antipsychotic Drugs • Typical – Examples: chlorpromazine (Thorazine), haloperidol (Haldol) • Atypical – Examples: clozapine (Clozaril), olanzapine (Zyprexa), risperidone (Risperdal) Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Table 17-5 Common Typical and Atypical Antipsychotic Drugs Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Table 17-5 (continued) Common Typical and Atypical Antipsychotic Drugs Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Table 17-5 (continued) Common Typical and Atypical Antipsychotic Drugs Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Table 17-5 (continued) Common Typical and Atypical Antipsychotic Drugs Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Antipsychotics: Uses • Act by blocking postsynaptic dopaminergic receptors • Used to decrease the positive symptoms of schizophrenia • Some agents are effective antiemetic and antinausea agents Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Antipsychotics: Adverse Effects • Common: sedation, dry mouth, sexual dysfunction, akathisia, bradykinesia, tardive dyskinesia Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Antipsychotics: Contraindications • Contraindicated in comatose patients who have received large amounts of CNS depressant drugs • Contraindicated in patients with known drug allergies to these agents Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Antipsychotics: Patient Information • Advise family members about adverse effects. • Suggest using hard candy or ice chips for a dry mouth. • Warn patient not to drive a car until effects are known. Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Lithium: Uses • Mechanism of action is unclear. • Used in control and prophylaxis of acute mania and in acute manic phase of mixed bipolar disorder Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Lithium: Adverse Effects • Common: nausea, tremors • Overdosage: vomiting, diarrhea, dizziness, headache, drowsiness, tinnitus, disorientation, short-term memory loss • Toxic levels: kidney and heart damage Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Lithium: Contraindications • Avoid in pregnancy and in patients with thyroid disorders. • Interacts with carbamazepine, haloperidol, and phenothiazines Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Lithium: Patient Information • Advise patients to drink plenty of fluids. • Instruct patients to contact their physician if diarrhea or fever develops. • Warn patients not to drink excessive caffeinated beverages and to avoid hot weather. • Warn patients not to drive until effects are known. Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Depression • Major depression affects about 5 to 6% of Americans. • Symptoms include feelings of doom, lack of self-worth, inability to sense pleasure, loss of energy, inability to concentrate, changes in sleep habits, thoughts of suicide. Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Antidepressants • Tricyclic antidepressants (TCAs) • Monoamine oxidase inhibitors (MAOIs) • Selective serotonin reuptake inhibitors (SSRIs) Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Table 17-6 Classifications of Antidepressants Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Table 17-6 (continued) Classifications of Antidepressants Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Mechanism of Action of Diazepam Animation Click on the screenshot to view an animation showing the mechanism of action of diazepam. Back to Directory Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini TCAs: Uses • Increase effects of norepinephrine and serotonin in the CNS by blocking reuptake by neurons • Used to treat endogenous depression and reactive depression Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini TCAs: Adverse Effects • Common: dry mouth, blurred vision, constipation, urine retention, tachycardia, mental confusion, sedation, postural hypotension • Serious: may precipitate hyperpyrexic crisis, tachycardia, or seizures Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini TCAs: Contraindications • Avoid in patients during acute recovery from myocardial infarction or with severe renal and hepatic impairment. Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini TCAs: Patient Information • Warn patients not to stop medication abruptly. • Advise patients to take at bedtime to promote a normal sleep pattern. • Instruct patients to report severe postural hypotension. • Educate patients that the drugs must be taken continually to be effective. Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini TCAs and Other Medications • Instruct patients to consult their physicians about taking any other medications, including OTC drugs, with TCAs. • Instruct patients to contact their physicians if allergic reactions occur while taking these medications. Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Effect of TCAs on Prostate Gland • Elderly men with enlarged prostate glands are at a higher risk for urine retention when taking TCAs. Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini St. John’s Wort • The natural product interacts with TCAs, MAOIs, SSRIs, alcohol, and foods high in tyramine or catecholamines. • Women should not use St. John’s wort during pregnancy or lactation. Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini SSRIs: Uses • Act by primarily blocking serotonin reuptake • Used to treat depression, geriatric depression, obsessive-compulsive disorder, bulimia nervosa, premenstrual dysphoric disorder Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini SSRIs: Adverse Effects • Common: headache, nausea, vomiting, tremor, insomnia, dizziness, diarrhea • Serious: cardiac toxicity and death from overdose Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini SSRIs: Contraindications • Do not use concurrently with MAOIs or thioridazine. • Do not use in pregnancy or in children younger than 7 years. • Use cautiously in patients with hepatic or renal impairment, renal failure, lactation, cardiac disease, and diabetes mellitus. Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini SSRIs: Patient Information • Advise patients to drive carefully while taking antidepressants, especially at the beginning of therapy. • Instruct patients to take in the morning with food to minimize insomnia and GI upset. • Warn patients to avoid alcohol. Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Monoamine Oxidase Inhibitors (MAOIs): Uses • May act by preventing natural breakdown of neurotransmitters • Used as second- or third-line antidepressants, depressive phase of bipolar disorder, and severe exogenous depression Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini MAOIs: Adverse Effects • Common: orthostatic hypotension, nausea, constipation, dry mouth, diarrhea, dizziness, vertigo, headache • Serious: hypertensive crisis Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini MAOIs: Contraindications • Avoid in patients with epilepsy, liver disease, and serious cardiovascular disease. • These drugs interact with many other drugs and with foods containing tyramine (cheese, yogurt, beef, coffee, tea, caffeinated sodas, chocolate, red wine). Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini MAOIs: Patient Information • Instruct patients to avoid foods that contain tyramine and provide a list of these foods. • Inform patients that effectiveness occurs after about 2 weeks of therapy. Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini