Analgesic efficacy of meperidine hydrochloride used alone and in combination with promethazine hydrochloride

Summary and Conclusions

Initially, 51 consecutive patients who had undergone hemorrhoidectomy were included in a double-blind, cross-over study to determine whether or not 50 mg. of meperidine would provide postoperative analgesia equivalent to 100 mg. of meperidine when the 50 mg. of meperidine was supplemented with 50 mg. of promethazine. Postoperatively, 40 of the 51 patients completed the cross-over study, nine required only one analgesic dose, and two did not require any medication for the relief of pain.

The results were tabulated and the data were interpreted on a statistical basis, according to analytic methods of Beecher and Herdan. There was no significant difference between the relief of pain afforded by one preparation as compared to the relief produced by the other. This was true for members of the cross-over group and members of the total group.

The side effects observed were insignificant, except for the marked decrease in blood pressure noted in several patients after the administration of meperidine. It would appear that the use of promethazine with meperidine diminishes the characteristic effect of meperidine. The addition of promethazine to the meperidine did not increase the number of patients who slept after the administration of the medication.

It can be concluded, therefore, that the addition of promethazine to a given amount of narcotic analgesic agent affords relief of pain comparable to that obtained by double the amount of narcotic analgesic agent alone. This conclusion substantiates what has been suggested in medical literature; namely, that promethazine potentiates the analgesic action of a narcotic agent.