New information points to safer methadone use for treatment of pain and...( New findings may significantly impro...),Health

New findings may significantly improve the safety of methadone, a drug widely used to treat cancer pain and addiction to heroin and other opioid drugs, according to researchers at Washington University School of Medicine in St. Louis and the University of Washington in Seattle.

The researchers discovered that the body processes methadone differently than previously believed. Those incorrect assumptions about methadone have been making it difficult for physicians to understand how and when the drug is cleared from the body and may be responsible for unintentional under- or overdosing, inadequate pain relief, side effects and even death.

For many years, methadone has been a mainstay in the treatment of opioid addiction. Taken orally, it suppresses withdrawal and reduces cravings. In recent years, doctors have prescribed methadone more frequently as an effective treatment for acute, chronic and cancer pain. Use of the drug for pain treatment rose 1,300 percent between 1997 and 2006. As more methadone was prescribed, however, adverse events increased by approximately 1,800 percent, and fatalities were up more than 400 percent (from 786 to 3,849) between the years 1999 and 2004.

"Unfortunately, increased methadone use for pain has coincided with a significant increase in adverse events and fatalities related to methadone," says principal investigator Evan D. Kharasch, M.D., Ph.D., an anesthesiologist and clinical pharmacologist at Washington University School of Medicine and Barnes-Jewish Hospital in St. Louis. "The important message is that guidelines used by clinicians to direct methadone therapy may be incorrect."

Kharasch, the Russell D. and Mary B. Shelden Professor and director of the Division of Clinical and Translational Research in Anesthesiology at the School of Medicine, and his colleagues report the findings in the March issue of the journal Anesthesiology and online in the journal Drug and Alcohol Dependence
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