Homsi, J., Walsh, D., Lasheen, W., Nelson, K.A., Rybicki, L.A., Bast, J., & LeGrand, S.B. (2010). A comparative study of 2 sustained-release morphine preparations for pain in advanced cancer. The American Journal of Hospice & Palliative Care, 27(2), 99–105.

To compare the efficacy, side effects, and use of rescue medication associated with two two-hour sustained-release morphine preparations: SR1 (MS Contin, Purdue Frederick Co., CN) and SR2 (Oramorph SR, Roxane Laboratories, Columbus, Ohio)

Patients' pain had been stabilized prior to treatment-group random assignment. Stabilization was defined as pain requiring fewer than four rescue doses in the previous 24 hours and pain rated as moderate or less for 48 consecutive hours. Patients were randomly assigned to SR1 or SR2 medication every 12 hours for five days. Investigators gathered data about side effects and compliance by means of daily telephone calls. Investigators assessed the acceptability of the medications at the end of the study, by asking patients if they wanted to continue taking the drug they were receiving.

• The sample was composed of 32 patients.
• Mean patient age was 63.5 years. The age range was 27–79 years.
• Of all patients, the percentage of females was 44% and the percentage of males was 56%.
• Most frequent cancer types were lung cancer and gynecologic and colorectal cancers. The majority of patients had metastatic disease.

• Single site
• Outpatient
• Cleveland Clinic, Cleveland, Ohio, United States

Randomized open-label, parallel-group trial

Five-point rating scale (0 = none, 4 = severe), to measure pain

Authors noted an overall trend toward lower pain rating scores in the SR2 group. This difference was statistically significant (p = 0.05)  on day 3 only. The total accumulative rescue dose over the study period was significantly higher for SR1 (p = 0.03). Authors noted no significant differences in side effects between the two groups. All patients taking SR2 elected to remain on that medication; 75% of patients preferred to continue taking SR1. Median morphine dose overall was higher in the SR1 group. The sample size was determined by power analysis.

The study suggests that, compared to SR1, SR2 may provide better analgesic efficacy, resulting in less overall need for rescue medication.

• The study had a small sample size, with fewer than 100 participants.
• The study used only one measure of pain intensity.
• The study duration was very short, just five days.

Findings suggest that the efficacy of various formulations of controlled- and sustained-release oral morphine preparations can be different. Nurses should be aware of this in the context of managing chronic pain. Researchers should undertake long-term studies to provide clinically relevant data in this regard.