Preanaesthetic medication with clonidine: a dose-response study.

Eighty normotensive female patients were studied in a randomized, double-blind investigation, in which orally administered clonidine 0.1 mg, 0.2 mg and 0.3 mg were compared with a standard benzodiazepine premedicant. Clonidine 0.2 mg produced a significant reduction in anxiety (P less than 0.05) compared with all the other groups, and a better quality of induction of anaesthesia when compared with temazepam 20 mg and clonidine 0.1 mg. The decreases in arterial pressure and heart rate with clonidine 0.3 mg were significant compared with the other treatment groups. Hypotension persisted into the postoperative period after premedication with clonidine 0.3 mg, and this dose is not recommended as a routine premedicant.