Kaplan + Sadock's Synopsis of Psychiatry, 11e

29.4  b -Adrenergic Receptor Antagonists

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Table 29.4-2 Psychiatric Uses for b -Adrenergic Receptor Antagonists

Laboratory Interferences The b -receptor antagonists do not interfere with standard labo- ratory tests. Dosage and Clinical Guidelines Propranolol is available in 10-, 20-, 40-, 60-, 80-, and 90-mg tablets; 4-, 8-, and 80-mg/mL solutions; and 60-, 80-, 120-, and 160-mg sustained-release capsules. Nadolol is available in 20-, 40-, 80-, 120-, and 160-mg tablets. Pindolol is available in 5- and 10-mg tablets. Metoprolol is available in 50- and 100-mg tablets and 50-, 100-, and 200-mg sustained-release tablets. Atenolol is available in 25-, 50-, and 100-mg tablets. Acebutolol is available in 200- and 400-mg capsules. For the treatment of chronic disorders, propranolol admin- istration is usually initiated at 10 mg by mouth three times a day or 20 mg by mouth twice daily. The dosage can be raised by 20 to 30 mg a day until a therapeutic effect emerges. The dosage should be leveled off at the appropriate range for the disorder under treatment. The treatment of aggressive behavior sometimes requires dosages up to 80 mg a day, and therapeutic effects may not be seen until the person has been receiving the maximal dosage for 4 to 8 weeks. For the treatment of social phobia, primarily the performance type, the patient should Other (rare) Raynaud’s phenomenon Peyronie’s disease Withdrawal syndrome Rebound worsening of preexisting angina pectoris when b -adrenergic receptor antagonists are discontinued Table 29.4-3 Adverse Effects and Toxicity of b -Adrenergic Receptor Antagonists Cardiovascular Hypotension Bradycardia Congestive heart failure (in patients with compromised myocardial function) Respiratory Asthma (less risk with b 1 -selective drugs) Metabolic Worsened hypoglycemia in diabetic patients on insulin or oral agents Gastrointestinal Nausea Diarrhea Abdominal pain Sexual function Impotence Neuropsychiatric Lassitude Fatigue Dysphoria Insomnia Vivid nightmares Depression (rare) Psychosis (rare)

Definitely effective

Performance anxiety Lithium-induced tremor Neuroleptic-induced akathisia Probably effective Adjunctive therapy for alcohol withdrawal and other substance-related disorders Adjunctive therapy for aggressive or violent behavior Possibly effective

Antipsychotic augmentation Antidepressant augmentation

Precautions and Adverse Reactions The b -receptor antagonists are contraindicated for use in people with asthma, insulin-dependent diabetes, congestive heart failure, significant vascular disease, persistent angina, and hyperthyroid- ism. The contraindication in diabetic persons is because of the drugs’ antagonizing the normal physiologic response to hypo- glycemia. The b -receptor antagonists can worsen atrioventricular (AV) conduction defects and lead to complete AV heart block and death. If the clinician decides that the risk-to-benefit ratio war- rants a trial of a b -receptor antagonist in a person with one of these coexisting medical conditions, a b 1 -selective agent should be the first choice, and the patient should be monitored. All cur- rently available b -receptor antagonists are excreted in breast milk and should be administered with caution to nursing women. The most common adverse effects of b -receptor antagonists are hypotension and bradycardia. In persons at risk for these adverse effects, a test dosage of 20 mg a day of propranolol can be given to assess the reaction to the drug. Depression has been associated with lipophilic b -receptor antagonists, such as pro- pranolol, but it is probably rare. Nausea, vomiting, diarrhea, and constipation can also be caused by treatment with these agents. The b -receptor antagonists may blunt cognition in some people. Serious CNS adverse effects (e.g., agitation, confusion, and hallucinations) are rare. Table 29.4-3 lists the possible adverse effects of b -receptor antagonists. Drug Interactions Concomitant administration of propranolol results in increases in plasma concentrations of antipsychotics, anticonvulsants, theophylline (Theo-Dur, Slo-bid), and levothyroxine (Syn- throid). Other b -receptor antagonists may have similar effects. The b -receptor antagonists that are eliminated by the kidneys may have similar effects on drugs that are also eliminated by the renal route. Barbiturates, phenytoin (Dilantin), and cigarette smoking increase the elimination of b -receptor antagonists that are metabolized by the liver. Several reports have associated hypertensive crises and bradycardia with the coadministration of b -receptor antagonists and monoamine oxidase inhibitors. Depressed myocardial contractility and AV nodal conduction can occur from concomitant administration of a b -receptor antagonist and calcium channel inhibitors.