Controlled-release morphine tablets in patients with chronic cancer pain - A narrative review of controlled clinical trials

BACKGROUND. Controlled-release (CR) morphine tablets have become routine therapy in the management of cancer pain. Compared with immediate-release (IR) morphine, this formulation provides the benefit of dosing every 12 hours. METHODS. This study reviewed the 10 published, well controlled, repeated-dose, comparative studies with CR morphine tablets administered every 12 hours to patients with cancer pain. RESULTS. CR morphine tablets were uniformly effective; 98% of patients completed a treatment course of every-12-hours therapy. Although the effective analgesic dose varied considerably from study to study (range, 90-330 mg per day), pain was well controlled with CR morphine tablets as the primary analgesic. Mean pain scores, converted to a common 10-point scale, ranged from 1.1-2.4 across all studies. There was only occasional need for IR morphine rescue medication (range, 2-39 mg per day). The mean discontinuation rate because of side effects or lack of every-12-hours efficacy was 2%. In seven studies that used IR morphine as the comparative agent, CR morphine tablets were found to be equally effective as IR morphine. CONCLUSIONS. Twice-daily dosing of CR morphine provides convenient, safe, and effective relief of cancer pain. (C) 1998 American Cancer Society.