A novel morphine sulphate preparation: clinical trial of a controlled-release morphine suspension in cancer pain

Abstract

In order to determine the efficacy of a novel controlled-release morphine suspension, we performed two prospective sequential open-label studies in patients with pain due to cancer. The studies were identical except for the duration of treatment (three days and 30 days respectively). Sixty-nine patients with a variety of advanced cancers and associated pain participated. Fifty-three patients completed the trials, 38 on the three-day trial and 15 on the 30-day trial. In both groups the amount of morphine required to obtain pain relief was initially established using controlled-release morphine tablets and immediate-release morphine for 'rescue' dosing. Patients were begun on equivalent doses of the study drug in place of the controlled-release tablets. No differences in pain score or the amount of 'rescue' morphine were noted following the switch to the controlled-release morphine suspension. Toxicity was as anticipated for the use of morphine in this situation and no adverse effects were observed during administration of the suspension. These data suggest that this new formulation of morphine is equipotent to conventional controlled-release morphine tablets and provides pain relief for a 12-hour dosing interval. This novel morphine formulation could be especially useful for paediatric patients and for those who have difficulty in swallowing.