Comparative study of two long-acting tranquillizers for oral premedication.

Lorazepam 2.5 mg was compared with promethazine 50 mg as oral premedication in a double-blind study in women. The premedication was given at the same time to all patients on each operating list, and both drugs continued to be effective 6 h after ingestion. A similar number of patients considered each drug to have relieved anxiety and the amnesic effect of lorazepam was confirmed. However, the use of lorazepam alone was accompanied by significantly more salivation during and after anaesthesia than the use of promethazine, especially in patients in whom the trachea was intubated. There was also a higher frequency of vomiting during and after operation with lorazepam (seven of 67 patients) than after promethazine (one of 71 patients). Promethazine produced dyskinetic side-effects in six of 71 patients.