[FONT=Verdana, Arial, Helvetica, sans-serif]Study Highlights Risk for Fatalities With Methadone[/FONT]
A disproportionate number of opioid-related overdose deaths involve methadone, new research suggests.
“While methadone is an excellent pain medicine, it is trickier to use than other opioids,” said investigator Lynn Webster, MD. “Our results suggest there may remain a knowledge deficit, even among pain experts, about how to use it.”
Between 2001 and 2005, deaths related to opioids increased by 260%, according to data from the Drug Enforcement Administration (Product No. 2009-L0487). LifeSource, a nonprofit group cofounded by Dr. Webster, medical director of Lifetree Pain Clinic, Salt Lake City, convened a panel of experts to study the reasons behind these deaths as part of its Zero Unintentional Deaths campaign, which aims to reduce opioid-related deaths.
The panel collected data from several sources: 91 PubMed, state and local reports on opioid-related fatalities; 35 malpractice suits involving opioids; and data from the Utah Department of Health campaign to reduce deaths from opioid use. The authors presented their findings in poster form (abstract 228) at the American Academy of Pain Medicine’s annual conference in San Antonio.
The panel found that methadone played a role in more deaths, proportional to outpatient prescriptions filled, than any other opioid. Although methadone makes up only 5% of opioid prescriptions (but still nearly 50 million in 2008), it accounts for about one-third of patient deaths.
Methadone-related calls to poison control centers, admissions to emergency rooms and malpractice suits exceeded those related to either hydrocodone or oxycodone. Adjusted for number of dispensed prescriptions, the panel found that four times as many calls to poison control centers were related to methadone as to oxycodone, and methadone played a role in 10 times as many calls as hydrocodone. Nearly one-third (30%) of emergency room visits for overdose involved methadone, six times as many as for oxycodone and 23 times as many as for hydrocodone. Finally, half of the 20 malpractice suits reviewed concerned fatalities involving methadone.
Starting dose and titration are critical to safe use, the panel’s review suggests. According to Utah data, 70% of decedents with a methadone prescription died within the first week of starting treatment. In over 80% of malpractice suits involving methadone or other opioids, death occurred within five days of starting a new dose.
For pain physicians, these findings suggest the need for much greater caution when prescribing methadone. In particular, Dr. Webster encouraged physicians to be aware of the dangers of conversion tables and sleep apnea. “Never use a conversion table,” he advised, because these tools may be inaccurate. Instead, “begin with a very low dose and titrate slowly.”
Sleep apnea is another serious risk associated with methadone use, according to the researchers. Although obstructive sleep apnea is correlated with body mass index, central sleep apnea—another risk associated with methadone—is not. “All patients on 50 mg or higher of methadone require a sleep study to assess risk,” said Dr. Webster.
Further contributing to methadone fatalities may be insurance company practices, he said. Some insurers require that patients try generic methadone or morphine before moving to brand-name drugs, Dr. Webster explained. When patients switch insurers, however, this policy sometimes requires them to shift from brand-name opioids to generic methadone, prompting physicians to use a conversion table and prescribe a dangerously high initial dose.
Jane Ballantyne, MD, professor of anesthesiology and critical care at the Hospital of the University of Pennsylvania, in Philadelphia, noted that methadone can be a “useful drug” for pain treatment and opioid rotation, but it is “highly unpredictable and very dangerous” if used incorrectly. While prescriptions for it have increased over the past several years, education is “very important” to its safe use, she said.
Although methadone requires special care, the authors of the study emphasized that it is not the only opioid to present challenges. As noted, their research indicated that two-thirds of opioid deaths resulted from other opioids, and they wrote, “all must be used judiciously.”