Changes in cerebral blood velocity after intravenous diazepam.

Cerebral blood velocity (CBV) was measured with transcranial Doppler in 6 normal right-handed male volunteers before and for 50 min after an intravenous injection of 0.1 mg/kg of diazepam and normal saline during 2 separate visits to the laboratory. Blood pressure, pulse rate, end tidal levels of carbon dioxide and mood changes were quantified before and after the injections. Diazepam injection was associated with significant increases in fatigue and sleepiness. There were no significant changes in end tidal carbon dioxide, respiration, pulse rate, and blood pressure after the injection. Postdiazepam CBV was significantly lower following diazepam compared to CBV following placebo.