Once-a-day morphine may give more constant pain control

A new once-a-day controlled-release morphine formulation appears to provide less fluctuation in plasma concentration and more stable pain control than an earlier twice-daily version of the agent, according to Canadian researchers.

Dr. Neil A. Hagen of the Tom Baker Cancer Center in Alberta, Calgary and colleagues note in the January 1st issue of the Journal of Pain and Symptom Management that twice-daily controlled-release morphine offers several advantages over shorter-acting formulations. These include better compliance, more convenience and less fluctuation in plasma drug concentration.The researchers undertook the current study to determine if a once-a-day controlled-release formulation (MS Contin XL) developed by Purdue Pharma, provided additional benefits compared to twice-a-day dosing with MS Contin.The double-blind, crossover study involved 25 patients with chronic cancer pain who were randomized to once-a-day or twice-daily morphine for one week. The following week, patients were given the alternate treatment.No between-group differences were seen in adverse events, pain intensity or analgesic efficacy. However, pain scores increased during the day on the twice-daily formulation. They did not increase while patients took the once-a-day drug. There was significantly reduced fluctuation in plasma morphine concentration with the once-a-day drug. There also was a trend toward less nausea among patients on the once-a-day formulation.Overall, 68% of patients said that they preferred the once-a-day formulation to twice-daily dosing for continued pain management.The investigators thus conclude that the once-daily morphine capsules “provide a valuable therapeutic alternative for this group of patients.” The research was supported by a grant from Purdue Pharma.(Source: J Pain Symptom Manage 2005;29:80-90: Reuters Health: Oncolink: February 2005.)