Treatment with benzodiazepines should be restricted to the short-term (two to four weeks only) relief of anxiety that is severe, disabling or causing extreme distress. Chronic use is not recommended. The lowest dose that can control symptoms should be used, reviewed regularly and discontinued as soon as possible. Withdrawal should be gradual as there is a real risk of precipitating a rebound syndrome even in patients who have been taking benzodiazepines for only a few weeks. The benzodiazepines marketed as anxiolytics can be divided into two groups:
Intermediate-acting compounds (lorazepam, oxazepam) carry a greater risk of withdrawal symptoms. There is however a minimal risk of excessive accumulation with these compounds.
Long-acting compounds (chlordiazepoxide, diazepam) have a smoother offset of action so withdrawal is usually less of a problem. Repeated doses may lead to accumulation of drug metabolites. The elderly and those with renal and/or hepatic impairment will be particularly susceptible to the adverse effects of these compounds.
Other anxiolytics include the β-blocker propranolol, which reduces the palpitations, tremor and GI upset that are commonly found in anxiety states and is consequently more effective for somatic than for psychic anxiety symptoms. Propranolol is probably less effective than the benzodiazepines, but offers a useful alternative in view of concerns over benzodiazepine dependence. Buspirone is chemically and pharmacologically distinct from other anxiolytics. It improves symptoms in the first week of treatment, followed by a progressive rate of symptom response. It produces less sedation, psychomotor impairment and dependence, and has less abuse potential than the benzodiazepines. It does not appear to interact with alcohol or other CNS depressants. Buspirone does not alleviate the symptoms of benzodiazepine withdrawal, so these should be withdrawn gradually if patients are transferred to buspirone.