Opioid Poisoning Danger High Even for Low-Dose Users

Opioids have been and continue to be a major source of relief for both chronic and acute pain sufferers. As the use of prescription opioid medications continues to rise, however, so does our knowledge about opioid dependence and opioid poisonings.

Pain management specialists are certainly aware of the risks of overprescribing, abuse, theft, and even opioid poisoning and guidelines for chronic opioid use are generally well-established in most states. Previous research has shown that both fatal and nonfatal opioid overdoses were more likely among chronic users and people with higher prescribed doses. But a new study in the current issue of Medical Care points to a lesser-known danger: opioid poisonings can impact even patients who are not chronic opioid users and who are prescribed low doses. Current prescribing guidelines focus on chronic users who take high doses of opioids.

The study examined changes in rates of methadone and other opioid poisonings since the implementation of the Washington State Opioid Guideline in 2007 and the prescription history of the patients before the poisonings. The study consisted of individuals who had at least 1 paid claimfor an opioid prescription in the Medicaid fee-for-service system between April 2006 and December 2010 and had an emergency department or inpatient hospital claim for an opioid poisoning.

The research identified 2,250 overdoses occurring in 1,809 patients. About 35% of these events were associated with methadone. In fact, methadone poisonings occurred at 10 times the rate of other prescription opioid poisonings and actually increased between 2006 and 2010 despite the advancement of the opioid prescribing guideline in 2007. Rates of other prescription opioid poisonings appeared to level off after implementation of the guideline.

Surprisingly, among individuals with nonmethadone opioid poisonings, only 44% had chronic opioid use; 17% had prescribed doses in the week before the poisoning >120 mg/d morphine-equivalent dose (MED), 28% had doses <50 mg/d MED, and 48% had concurrent sedative prescriptions.

The study authors would like to see revised guidelines that take into account the danger to patients taking low-dose medications, including prescription sedatives, which are involved in as many as half of all opioid overdoses.