Antianxiety drugs: clinical pharmacology and therapeutic use.

It is difficult to choose among the many drugs advocated for treating anxiety symptoms. The barbiturates were the most commonly used antianxiety agents until recently but are being superseded by the benzodiazepines. The latter are more effective than the barbiturates as shown in comparative clinical trials, they are safer in overdosage (deliberate or accidental), and they are somewhat less likely to induce dependence. The barbiturates have the additional drawback of interfering with the action of other drugs by inducing liver microsomal (oxidising) drug metabolising enzymes. The major tranquilisers (neuroleptics or antipsychotics) are often of value in low dosage in patients with a previous history of dependence on alcohol, the barbiturates or the benzodiazepines. Tricyclic antidepressants are the treatment of choice in anxious and depressed patients and monoamine oxidase inhibitors may be helpful in phobic patients. The beta-adrenoreceptor blocking agents such as propranolol often ameliorate somatic symptoms such as palpitations and tremor. In the treatment of anxious patients it is important to remove causes for anxiety and to limit any course of drug treatment to a finite period. Both dosage level and dosage interval should be flexible. Benzodiazepines remain the drug treatment of choice.