The use of flumazenil in the management of acute drug poisoning--a review.

The popularity and widespread availability of benzodiazepines (BZD) has led to their frequent abuse in intentional drug poisoning. Although mortality from pure BZD overdose is usually small, in elderly, debilitated patients, or when BZD are combined with other CNS depressant drugs, morbidity increases significantly and outcome may be fatal. Drug overdose is therefore a medical emergency necessitating close observation and support of vital functions. Recently, the specific BZD antagonist flumazenil (Anexate) has become clinically available and much experience in its usefulness has accumulated. The present review summarizes a total of 30 studies and reports published to date, involving approximately 760 intoxicated patients. Flumazenil was evaluated both in prehospital use as well as in emergency rooms or in intensive care units. The age of patients ranged from 4-90 years and doses of flumazenil varied between 0.3-10 mg, approximately 1 mg being the most frequently used. All patients intoxicated with only BZD returned to full consciousness within minutes after the injection of flumazenil. When a mixture of BZD and other CNS depressants was abused, a range of effects was observed. This varied from no change to a return to full orientation, depending on the contribution of the BZD to the state of unconsciousness. Re-sedation occurred in about 65% of flumazenil treated patients, usually within 0.5-3 h after the first dose, the shorter interval being associated with mixed-drug poisoning. Repeated doses of the antagonist (0.2-2 mg), sometimes followed by continuous infusion (0.1-0.5 mg/h), were effective in maintaining patients fully oriented.(ABSTRACT TRUNCATED AT 250 WORDS)