Benzodiazepines in the treatment of sleep disorders: pharmacokinetic aspects

In order to avoid after-effects during the day, slowly eliminated hypnotic agents should not be used in the treatment of sleep disorders. It has become customary to separate long-acting from short-acting benzodiazepines and to use the (terminal) half-life as the principle of classification. This approach is only justified, however, in the case of quickly absorbed benzodiazepines that have no pharmacologically active metabolites and that exhibit one-compartment disposition kinetics. In contrast, the duration of action of benzodiazepines characterized by marked two-compartment disposition kinetics can only be estimated correctly when the potency and all relevant kinetic parameters of the drug preparation and its pharmacologically active metabolites are considered.