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NEW YORK (Reuters Health) - Patients prescribed higher doses of powerful painkillers are more likely to die of an accidental overdose on those drugs, according to a new study.
The finding is the latest addition to the debate in the medical community over how to balance the needs of patients in severe pain against the high potential for misuse and abuse of opioid drugs, which include Oxycontin and Vicodin.
"There's been some push and pull back and forth around this balance of, are we too conservative and under-treating pain as a result ... or are we using (opioids) too much and putting people at risk?" Dr. Amy Bohnert, a psychiatrist at the University of Michigan Medical School in Ann Arbor and the lead author of the study, told Reuters Health.
The number of people who both abuse opioid drugs and who overdose has been increasing in the U.S. in recent years, and about 200 million prescriptions for opioids are dispensed each year.
However, the authors point out, the risk of dying of an accidental overdose, even in patients on high doses of painkillers, was still small - less than half a percent, at most.
Bohnert and her colleagues examined data from patients treated through the Veterans Health Administration between 2004 and 2008. Over that time, there were 750 deaths from accidental overdoses on opioids out of an estimated 1.8 million people treated with the drugs - or about 4 for every 10,000 patients with a prescription.
To find out whether any particular characteristic might signal that a person was at higher risk for such a problem, the researchers compared the people who died of an overdose with those who didn't.
They found that patients who were prescribed higher doses - and thus had access to more painkillers at any given time - were more likely to accidentally overdose.
For example, patients suffering from chronic or acute pain who were prescribed opioids at 100 milligrams per day or higher were between 6 and 8 times more likely to overdose than those with prescriptions for 1 to 20 mg/day.
Painkiller users who accidentally overdosed were also more likely to have problems with substance abuse or to suffer from mental illness, according to the findings, which are published online today in the Journal of the American Medical Association
In certain cases a high dose of opioid narcotics is appropriate. For cancer patients, for instance, the National Cancer Institute (NCI) advises that when an opioid doesn't give enough pain relief, doctors may increase the dose or have the patient take the painkiller more often, or prescribe a stronger drug. "Both methods are safe and effective under your doctor's care," the NCI says on its web site. But patients must not increase the dose of medication on their own, the NCI emphasizes.
Bohnert said that there are likely two explanations behind the pattern she and her colleagues observed. The first, she said, is that people on higher doses of opioids have more opportunity to accidentally take too much medication in the course of their normal treatment.
The other explanation is that some patients with chronic pain intentionally misuse their drugs, saving them to use recreationally, and then overdose in that context.
Whether a particular patient in pain is at risk for misusing or abusing their drugs is something that should be considered whenever heavy-duty painkillers are being prescribed, Bohnert said.
Doctors, patients and their families "can work together to decide what is the right treatment for that patient," she said. Then, they can "weigh the balance of untreated pain with the risk of overdose on a patient-by-patient basis."
Dr. Nora Volkow, the director of the National Institute on Drug Abuse, and colleagues also reported in this week's JAMA that many patients taking opioid medications get them from multiple doctors or dentists at the same time.
Along with more open discussion about the risks of pain medications between doctors and patients, she said there needs to be better monitoring in place so that doctors can see which patients might be abusing their drugs and getting them from multiple sources.
But addressing the problem of opioid-related overdoses is not as simple as trying to cut down on cocaine abuse, for example, Volkow said.
"It is a problem that we're facing of the abuse of a substance that has very unique therapeutic purposes and can be life-saving," Volkow told Reuters Health. "We cannot get rid of pain medications."
SOURCE: bit.ly/hwxtTL Journal of the American Medical Association, online April 5, 2011.