OHSU researchers find methadone may cause cardiac arrest

Methadone, a drug once used mainly to help heroin withdrawal symptoms but now increasingly used for pain relief, can cause sudden cardiac death even at the levels prescribed by physicians, according to a study published Thursday by an Oregon Health and Science University researcher. Until a decade ago, methadone was prescribed almost exclusively to help heroin addicts deal with the effects of withdrawal. But in recent years, physicians have turned to the drug for chronic pain relief, because the generic synthetic opiate costs a fraction of other painkillers such as Vicodin and OxyContin. The new study says patients taking methadone for any reason are at increased risk of cardiac arrest, regardless of the dose or whether they have any previous heart conditions. In recent years reported deaths among people taking methadone have increased dramatically, but most reports focused on the dangers of overdosing. One of the appeals of methadone for pain relief is that it is very long lasting. One dose can remain in the body for up to 36 hours, increasing the possibility of overdose among people who take a second dose while the drug remains in their system. In fact, Oregon ranks among the states with the highest rates of death from methadone. The per capita rate of methadone deaths increased 1,250 percent between 1999 and 2004, according to data from the federal Centers for Disease Control and Prevention. The new report says that even properly dosed, methadone can kill. And the rate of death may be much higher than public health officials previously suspected. OHSU cardiologist Dr. Sumeet Chugh, lead researcher on the study, said he first suspected there might be a relationship between methadone and sudden cardiac death when the Oregon Health Division sent out an alert four years go that said death rates among methadone patients in Oregon had quadrupled. Methadone, he said, has been known to affect cells of the heart, which can lead to cardiac arrest. Chugh leads the Oregon Sudden Unexpected Death Study at OHSU, which has given him access to study all cases of sudden cardiac arrest that occur in the Portland metropolitan area. Working with the state medical examiner, Chugh looked at 22 Portland-area cases of death in which people had therapeutic, but not lethal, levels of methadone in their blood. Looking for possible explanations for their cardiac arrest, he compared the methadone users with a control group of people who had died in Multnomah County from unexplained cardiac arrest. According to Chugh, 77 percent of the deaths studied among people who had methadone in their system had no heart abnormalities that could have explained their sudden cardiac death. In the control group — people who had no methadone in their blood when they died — only 40 percent had no apparent cause for their cardiac arrests. Chugh said the data tell him that methadone must have been responsible for many of the unexplained cardiac deaths. “Methadone is clearly implicated with a higher rate of cardiac arrest,” Chugh said. But he cautioned that his data do not reveal the actual risk of cardiac arrest for methadone users. That, he said, will only come from the next step — following a group of people who use methadone and recording their rate of death. Twelve of the 22 cases that Chugh studied involved patients who were using the drug for pain control. Only three were using the drug to fight drug addiction. Chugh said both groups need to approach using methadone with a new awareness. “We’re not saying stop using methadone,” Chugh said. “But what we’re saying is there are more judicious ways of using methadone. If people can afford it, perhaps we should look for alternatives.” Chugh said he has talked about his findings with physicians who prescribe methadone. “They have some level of concern but they are quite guarded,” he said. “It’s almost as if they feel if we take methadone away, what are their patients going to do?” Chugh said he published his findings in this month’s issue of The American Journal of Medicine, which is widely read by primary care physicians, rather than in a cardiology journal, where his work usually appears, precisely because he believes primary care physicians who prescribe methadone need to be aware. “This is a public health issue, and it’s bang in the middle of primary care,” he said. This email address is being protected from spambots. You need JavaScript enabled to view it.

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