Management of cancer pain with oral controlled-release morphine sulfate.

Morphine sulfate Contin (MSC) is an investigational matrix delivery system for oral morphine sulfate that allows for prolonged blood levels of morphine. Twenty-six patients with inadequately controlled cancer-related pain were examined in an open but controlled study using MSC. Initially, all patients were converted from the prestudy analgesic regimen to an equianalgesic amount of immediate-release morphine sulfate (IRMS) on a q4h dose schedule that was in turn titrated to the level of adequate pain relief. Patients then were switched to MSC q8h and eventually to q12h, starting at doses representing the same total daily amount of morphine that was in the final IRMS dose. Of the 18 patients who completed the study, all achieved satisfactory levels of analgesia on MSC, seven at q8h and 11 at q12h dosing intervals. All patients reported better analgesia while taking MSC compared with their previous regimen. Side effects associated with MSC included sedation and constipation but not nausea or respiratory difficulty. Significant drug tolerance did not develop during a mean follow-up period of four weeks (range, 1-18 weeks). MSC is an effective oral opioid analgesic that allows an increased dose interval without increased side effects or decreased potency. It can improve the quality of life of cancer patients by allowing them to be maintained without frequent dosing or parenteral medication.