Flurazepam hcl is a relatively old and widely used benzodiazepine hypnotic. The long half-life of its active n-desalkyl metabolite may be responsible for residual ('hangover') effects which extend into the day following ingestion of the recommended therapeutic dose (30 mg). A year-long investigation of flurazepam's residual effect on actual automobile driving performance was undertaken in two parts: an acute experiment and a subchronic experiment. The practical relevance of the results were discussed. The major conclusions were as follows: (1) flurazepam 30 mg impairs driving performance for at least 17 hours following drug intake; (2) flurazepam's residual effect is dose-dependent; and (3) frankly unacceptable impairment can occur in some individuals. The major recommendations were as follows: (1) the recommended flurazepam dose for patients who must operate vehicles on days following night-time drug use should not exceed 15 mg. (2) patients who require a higher flurazepam dosage nightly should refrain from driving for at least a week and preferably longer, after the beginning of therapy; and (3) the occasional use of flurazepam over shorter periods by drivers should be strongly discouraged.
Abstract