Methylnaltrexone, a drug designed to reverse one of the most troubling problems caused by opium-based analgesics without interfering with pain relief, is rapidly effective at low doses with no apparent side effects report researchers from the University of Chicago Medical Center in the January 19, 2000, issue of JAMA.
More than 250,000 terminal cancer patients each year take opioids, such as morphine, for pain relief. About half of those patients experience severe constipation. The discomfort can be so great that many patients choose to forego the pain relief in order to avoid the constipation.
In this double-blind, placebo-controlled study, methylnaltrexone promptly reversed opioid-induced constipation. In more than 90 percent of patients, relief came within one minute of the first infusion.
"By preventing this debilitating but little-discussed problem, methylnaltrexone could substantially enhance the quality of the last months of life for terminal cancer patients and others who depend on opioid pain relievers," said the study's first author Chun-Su Yuan, M.D., Ph.D., assistant professor of anesthesia and critical care at the University of Chicago.
"Our current challenge," notes his co-author Joseph Foss, M.D., assistant professor of anesthesia at the University of Chicago, "is to make this drug available to the patients who need it, so that they won't have to choose between inadequate pain relief and debilitating constipation."
Methylnaltrexone has been intensively studied, primarily at the University of Chicago, but with only limited support from the pharmaceutical industry.
"The costs of developing a new drug are substantial," explained Foss. "With a medication designed for short-term use by a fairly small group of users -- fewer than 150,000 people -- manufacturers may fear it would be difficult to recoup that investment, b
Contact: John Easton
University of Chicago Medical Center