Premedication with temazepam in minor surgery. The relationship between plasma concentration and clinical effect after a dose of 40 mg.

Fourteen patients received oral premedication of temazepam in soft gelatin capsules before minor surgery. The plasma concentrations of temazepam and its sedative, anxiolytic and amnesic effects were measured for 24 hours. Absorption was rapid and peak concentrations occurred 49 minutes after administration. Clinical effects were evident at 30 minutes and persisted for about 4 hours. The decline in plasma concentration was biexponential with a distribution half-life of 1.24 hours. The end of the distribution phase coincided approximately with the termination of its clinical effects. A relationship between plasma concentration and effect was observed; concentrations above 300 ng/ml produced measurable changes in tests of mental function. Patients had recovered fully from the effects of temazepam after 24 hours. This dose of temazepam is reliable and effective as premedication before surgery.