Clinical Evaluation of the Analgesic Effect of Sustained Release Morphine Sulfate Microgranules in Patients with Terminal Cancer

Summary

A randomised controlled clinical trial evaluating the analgesic effect of capsules containing sustained release (SR) morphine sulfate microgranules (M-Eslon®) was conducted in 120 patients with terminal cancer and moderate or severe pain. SR morphine sulfate as a tablet formulation (MS-Contin®) was used as the control drug. Both drugs were administered orally at dosages of 20mg (lower dosage) or 30mg (higher dosage) every 12 hours for 7 days. The parameters for pain assessment were pain intensity, evaluated on a 1 to 10 numerical rating scale, and pain relief (PAR), evaluated on a 5-grade scale.

The efficacy rates (the percentage of patients with PAR grades 2 to 4,12 hours postdose on day 7) in groups given SR morphine sulfate microgranules or tablets at the lower dosage were 76.7% and 83.3%, respectively, on the last day of treatment. The respective rates for the higher dosage groups were 83.3% and 80.0%. There was no significant difference between the 2 drugs in analgesic efficacy. SR morphine sulfate microgranules or tablets did not significantly influence respiratory, cardiovascular, haematological, hepatic or renal functions.

The adverse effect profile for SR morphine sulfate microgranules was similar to that for the tablets, the most frequent events being drowsiness, dizziness, gastric discomfort, nausea, vomiting, itching, difficulty urinating and constipation. The incidence of constipation tended to increase during the 7-day study period in both drug groups.