A controlled study of sustained-release morphine sulfate tablets in chronic pain from advanced cancer

The purpose of this double-blind crossover study was to determine whether a sustained-release morphine sulfate (SRMS) tablet given orally every 12 hours could adequately replace immediate-release morphine sulfate solution (IRMS) given orally every 4 hours in hospitalized patients with chronic pain from advanced cancer. Of 33 patients entered, 27 completed the study and were included in the efficacy and safety analysis. Patients were initially randomized to receive either 30-mg SRMS tablets every 12 hours or IRMS at the same mg/24 hours dose, every 4 hours. After 2 days, a crossover was performed, and patients received the alternate treatment for 3 days. Pain and side effects were assessed using a standard 100 mm visual analogue scale (VAS). There were no statistically significant differences between the two treatment groups for mean VAS pain scores or scores for sleepiness, nausea, depression, and anxiety. The incidence of breakthrough pain was similar for both treatment groups, as was the incidence of confusion and constipation. The results demonstrated that SRMS is a safe, effective analgesic preparation for patients who require oral opioids for cancer pain. The data also support the conclusion that sustained-release morphine tablets administered every 12 hours can replace an immediate-release morphine solution administered every 4 hours.