A new study appearing online this week in JAMA Internal Medicine draws significantly different conclusions on the risks of methadone therapy for pain than had been indicated in previous research. The study reports that outside the hospital, use of methadone to treat pain carries a 46% increased risk of death when compared to the equally effective but more costly alternative, morphine SR (sustained release). The research was conducted at Vanderbilt University Medical Center.
A side effect of opioid therapy is repressed respiration, but methadone is apparently unusual in that the analgesic effect is more short-lived than the respiration effect. This, the authors contend, may prompt patients to inadvertently overdose themselves. An additional concern is that methadone is a pro-arrhythmic drug that can trigger lethal ventricular arrhythmias. In 2009, some 4.4 million methadone prescriptions were written in the US for treatment of pain. The study reports that methadone’s higher risk ratio translates to 72 excess deaths per every 10,000 person-years of treatment, compared to morphine SR. The sole previous study comparing these 2 drugs produced a nearly opposite result: 44% decreased mortality with methadone.
Read a news story about the study findings here.