The efficacy and plasma concentrations of flunitrazepam after oral or intramuscular premedication.

Flunitrazepam premedication administered orally or intramuscularly was compared in 41 surgical patients. The effect of the premedication was assessed both subjectively and objectively. The plasma concentrations were determined just before induction. The mean (+/-SD) plasma concentration in the oral premedication group was 8.2 +/- 2.2 ng/ml and 7.9 +/- 4.6 ng/ml in the intramuscular premedication group. There was a highly significant correlation (p less than 0.001) between the sedative effect and plasma concentration of flunitrazepam in all patients. Oral flunitrazepam was equal to i. m. flunitrazepam as an anxiolytic and sedative with a rapid onset of action. However, the oral route of administration of flunitrazepam is preferable because it is painless and easy to administer.