Experience with a controlled-release oral morphine for cancer pain management

An open pilot study was performed to assess the analgesic efficacy and acceptability of a controlled-release oral morphine preparation. Between March 1989 and August 1990, 50 patients were treated with MS Contin (morphine sulphate tablets - MS Continus) for the pain caused by advanced cancer. The participants consisted of 28 males and 22 females ranging in age from 8 to 78 years (median 52 years). Twenty-two patients were actively receiving either cancer chemotherapy (15 patients), radiotherapy (2 patients), combined chemoradiotherapy (3 patients) or hormonal treatment (2 patients). Most of the subjects had pain caused by visceral disease and bone metastasis. A combination of causes was also present in 19 patients. The patients had a wide variety of cancers the most common being stomach cancer. In 24 patients, concomitant non-opioid or non-morphine opioid analgesics were combined with MS Contin. The median duration between cancer diagnosis and MS Contin initiation was 11.0 months. MS Contin was given on average for 1.5 months. The median survival after study enrolment was 1.8 months. Of the 50 enrolled patients, three left the study in the early phase due to drug-related adverse effects. In almost all the patients the effective dose was 60 mg/day with 45 days of response duration. The required duration for dose adjustment was nine days. The most common side effects were constipation and vomiting, which were controlled with conservative care. Two patients withdrew because of intractable vomiting and one because of mental drowsiness. In conclusion, twice-a-day moderate dose oral MS Contin therapy for cancer pain offers effective pain relief with minimal, tolerable side effects in the majority of patients in Korea.