Placebo-blinded study of morphine sulfate sustained-release tablets and immediate-release morphine sulfate solution...

This study was conducted to compare the relative analgesic efficacy and safety of an every-4-hour immediate-release oral morphine (IRM) solution with that of an every-12-hour sustained-release oral morphine (SRM) formulation.

This was a double-blind, placebo-blinded, crossover study in 34 adult male and female outpatients with pain due to advanced cancer. Baseline data were collected on day 1. On days 2 and 3, randomly assigned patients received either placebo plus IRM (Roxanol; Roxane Laboratories, Inc, Columbus, OH; 20 mg/mL) at 2, 6, and 10 am, and 2, 6, and 10 pm, or alternatively SRM (Oramorph SR; Roxane Laboratories, Inc; 30 mg) at 10 AM and 10 PM. Patients were then crossed over to the alternate treatment for days 4 through 6. Pain relief was measured using a conventional 100-mm visual analog scale (VAS) and by recording the incidence of breakthrough pain. Information on side effects was obtained from VAS scores for sedation, nausea, anxiety, and depression; by directly questioning the patient as to mental confusion, bowel movements, and laxative use; and from Karnofsky performance status scores. VAS data were analyzed using a linear statistical model. Breakthrough pain data were analyzed using analysis of variance (ANOVA).

There were no statistically significant differences between IRM and SRM treatments with respect to VAS pain scores, side effect scores, or incidence of breakthrough pain data. Karnofsky performance scores remained stable for all patients throughout the study.

It was concluded that every-12-hour administration of SRM and every-4-hour administration of IRM provide similar analgesic effectiveness and side effect profiles in the treatment of chronic pain in cancer patients.