Morphine and promethazine as intravenous premedicants.

Two hundred seventy patients received morphine 5 mg or 10 mg alone or with promethazine 6.25 mg, 12.5 mg, or 25 mg. Promethazine 25 mg alone also was studied. All drugs were given intravenously. Anxiety relief, sedation, patient acceptance, lack of recall, and side effects were the variables examined. Promethazine improved relief of anxiety, sedation, and patient acceptance when added to morphine. Doses of promethazine larger than 12.5 mg intravenously failed to improve these effects. Memory remained unaffected by any of the drugs.