ROLE OF RECTAL ROUTE IN TREATING CANCER PAIN - A RANDOMIZED CROSSOVERCLINICAL-TRIAL OF ORAL VERSUS RECTAL MORPHINE ADMINISTRATION IN OPIOID-NAIVE CANCER-PATIENTS WITH PAIN

Purpose: The aim of this double-blind, double-dummy, crossover study w as to compare the efficacy, tolerability, and time of onset of analges ia after the administration of 10 mg of morphine hydrochloride via the oral and rectal routes in opioid-naive cancer patients with pain. Pat ients and Methods: Thirty-four patients with cancer patients with pain . opioid treatment were randomized to receive morphine hydrochloride 1 0 mg orally or rectally (in the form of a microenema) for 2 days. Duri ng days 3 and 4, a crossover rook place. The scores of pain, nausea, a nd sedation (visual analog scale of 0 to 100) calculated as the percen tage change from baseline (before opioid administration) were assessed at different intervals up to 240 minutes. The number of vomiting epis odes was recorded. Parity tests and analysis of variance (ANOVA) were performed to compare the two administration routes. Results: A signifi cant difference in pain intensity was achieved 10 minutes after rectal administration compared with 60 minutes after oral administration. Th ere was still a significant reduction in pain via the rectal route aft er 180 minutes versus via the oral route after 120 minutes. No signifi cant difference was observed in the intensity of sedation, nausea, or number of vomiting episodes between the oral and rectal routes. Conclu sion: A liquid solution of morphine is well absorbed via the rectal ro ute. Rectal morphine is safe, effective, easy to manage, and inexpensi ve, with a rapid onset of action. Rectal morphine can be considered a valid alternative route for opioid administration and may also be used when rescue doses of morphine are required in patients regularly trea ted with oral or parenteral opioids. J Clin Oncol 13: 1004-1008. (C) 1 995 by American Society of Clinical Oncology.