Clinical pharmacology and therapeutics of benzodiazepines.

Benzodiazepines are among the most commonly prescribed drugs in the world. In contrast to their extensive use, the therapeutic indications and potential of benzodiazepines are limited. All benzodiazepine derivatives available in Canada are similar structurally and in their pharmacologic actions. Few have specific advantages over any others. For example, no benzodiazepine has been shown to be superior to chlordiazepoxide in the treatment of acute anxiety, chronic anxiety neurosis or insomnia. Barbiturates should not be prescribed for these problems since benzodiazepines are just as effective and are safer. Persons more than 70 years old should receive initial doses of benzodiazepines 50% less than those prescribed for younger persons, and individuals with cirrhosis should receive chlordiazepoxide or diazepam in one third the usual dose; oxazepam or lorazepam should be considered for these two groups of patients. Diazepam and chlordiazepoxide should not be given intramuscularly. Benzodiazepines should be prescribed only when clearly indicated and only for the necessary length of time.