Since methotrimeprazine has been used successfully for the past few years in Europe and Canada for a wide variety of painful conditions1-6 and has recently been shown by Lasagna and DeKornfeld7 to compare favorably with morphine in relieving postoperative pain, a trial was set up to compare the analgesic activity of these two drugs in several diseases. A simple design wherein single subcutaneous injections of each drug were given randomly as coded medications was utilized in this study. In general it was shown that a 15 mg. dose of methotrimeprazine hydrochloride provided analgesia comparable in degree to a 10 mg. dose of morphine sulfate.
The degree of analgesic activity of methotrimeprazine makes this drug unique among currently available phenothiazides. The activity of its parent compound, chlorpromazine, has been both weaker and less reproducible.2,7 Sigwald and co-workers1,2 reported methotrimeprazine to be the most effective phenothiazine for pain.
MONTILLA E, FREDERIK WS, CASS LJ. Analgesic Effect of Methotrimeprazine and MorphineA Clinical Comparison. Arch Intern Med. 1963;111(6):725–728. doi:10.1001/archinte.1963.03620300045008