Recovery and skills related to driving after intravenous sedation: dose-response relationship with diazepam.

Skills related to driving, the ability to discriminate the fusion of flickering light, and hand and foot proprioception, were measured double-blind in 34 healthy volunteers before and after three doses of i.v. diazepam. The effects of diazepam were most harmful to co-ordination. With 0.15 mg/kg, 0.30 mg/kg and 0.45 mg/kg of diazepam the impairment of co-ordinative skills was statistically significant (P less than 0.05) up to 2, 6 and 8 hr respectively. No impairment of performance on any test was measurable at 6 hr after 0.15 mg/kg or at 10 hr after 0.30 or 0.45 mg/kg of diazepam. There were large interindividual variations in serum concentrations of diazepam within each dose level. The increases in serum concentrations of diazepam after the intake of food support the concept of an enterohepatic cycle for diazepam. It was concluded that patients should not drive or operate machinery for at least 6 hr after 0.15 mg/kg of i.v. diazepam and at least 10 hr after 0.30 mg/kg and 0.45 mg/kg.