Overdose from prescription opioids (e.g., Oxycodone or Hydrocodone) has become one of the most common causes of accidental death in the United States. Two new articles in BMJ suggest that overdose is not the only risk about which patients, prescribers and policy makers should be concerned.
Khademi and colleagues conducted a prospective study of a cohort of 50,045 Iranians. They followed up over 99 percent of the sample and then assessed the impact of opium use on mortality. After statistically adjusting for cigarette smoking, education, age and other factors, the research team reported that opium use nearly doubled the risk of death. The number of diseases with increased incidence among opium users was large, and included tuberculosis, cancer and COPD. The results held even when the researchers excluded from analysis individuals who started using opium in response to the onset of a chronic illness.
These results do not necessarily generalize to prescription painkillers such as Oxycontin. Unlike opium, which comes directly from the poppy flower, modern, synthetic opioids are free of impurities and are never smoked. Further, opium use in Iran may be a marker for other risk factors (e.g., poor self-care habits or social isolation) for which the epidemiological study could not fully adjust.
That said, in an accompanying commentary in BMJ, Dhalla notes that preliminarystudies have found indications of higher death rates in patients who take opioid medications (versus, for example, NSAIDs). The increased death rates are not simply attributable to accidental overdoses. None of these studies of prescription opioids is definitive, but they certainly justify a larger replication research effort along the lines of the Iranian study of opium users.
The worrisome fact about prescription opioids is that their use has grown (.pdf) extraordinarily rapidly in a very short period in the United States, to over 200 million prescriptions in 2010 alone. As a result, any adverse impacts of opioids that take a few years to accrue may hit the population in a tidal wave before there is time to understand and prevent the damage.
Addiction expert Keith Humphreys, PhD, is a professor of psychiatry and behavioral sciences at Stanford and a career research scientist at the Palo Alto VA. He recently completed a one-year stint as a senior advisor in the Office of National Drug Control Policy in Washington.
Photo by Ingrid Taylar