Miscellaneous Medications in psychiatric practice

This section includes medications that are commonly used in psychiatric practice but that do not fall into the conventional categories of psychotherapeutic drugs. Many medications used in general medical practice have side effects such as sedation, stimulation, or anxiolysis. Thes side effects are often exploited in psychiatry to target specific symptoms (e.g., insomnia, anergia). Other drugs, such as psychostimulants, have precise indications for psychiatric usage. Many more medications than are discussed here are included in the psychiatric armamentarium.

Psychostimulants

Psychostimulants are used in psychiatry to treat attention deficit disorder, narcolepsy, and some forms of depression (Table 15-1). The most commonly used psychostimulants are dextroamphetamine (Dexedrine), methylphenidate (Ritalin), and pemoline (Cylert).

The mechanism of action of these medications appears to occur through their alterations of central nervous system (CNS) monoamine function. Their primary mechanism of action is thought to be facilitating endogenous neurotransmitter release (rather than acting as a direct agonist).

Psychostimulants have the liabilities of inducing tolerance and psychological dependence, which may lead to abuse. The side effects of these medications are due largely to their sympathomimetic actions and include tachycardia, insomnia, anxiety, hypertension, and diaphoresis. Weight loss may be an unwanted side effect in young children but a desirable one in overweight adults.

Anticholinergics

Medications with anticholinergic activity are commonly used in psychiatry to treat or provide prophylaxis for some types of neuroleptic-induced movement disorders (Table 15-1). Anticholinergics are generally used as first-line agents in the treatment of neuroleptic-induced parkinsonism and for acute dystonia; they may also have some utility in treating akathisia but are best tried after beta blockers and lorazepam. The most commonly used anticholinergics are benztropine and trihexyphenidyl. In addition, diphenhydramine, an antihistamine that also possesses anticholinergic properties, is frequently used to treat neuroleptic-induced movement disorders and to provide nonspecific sedation. These medications are CNS muscarinic antagonists.

Side effects of anticholinergics, due to peripheral anticholinergic action, include blurry vision (due to cycloplegia), constipation, and urinary retention; their principal central side effects are sedation and delirium. Anticholinergic toxicity is a major cause of delirium, especially in individuals with dementia and HIV encephalopathy.

Beta Blockers

Beta blockers are used widely in general medicine. In psychiatry, they have a few specific indications (see ). Beta blockers likely alter behavior and mood states by altering both central and peripheral catecholamine function. For example, in anxiety, they may diminish central arousal; peripherally, they may reduce tachycardia, tremor, sweating, and hyperventilation. Common side effects of beta blockers include bradycardia, hypotension, asthma exacerbtion, and masked hypoglycemia in diabetics. Beta blockers may also produce depression-like syndromes characterized by fatigue and depressed mood.