Of the 22,134 drug overdose deaths involving pharmaceuticals in the United States in 2010, three-fourths involved opioid analgesics, according to an analysis by officials from the Centers for Disease Control and Prevention (CDC).

In a research letter published in the Journal of the American Medical Association (2013;309:657-659), Christopher M. Jones, PharmD, a health scientist with the CDC’s Injury Center, in Atlanta, and two o his colleagues, parsed data from the National Vital Statistics System multiple cause-of-death file. The file contains information gleaned from death certificates submitted to the CDC by medical examiners or coroners.

They determined that 57.7% (22,134) of the 38,329 drug overdose deaths in the United States in 2010 involved prescription pharmaceuticals. The top drugs that were involved in those overdose deaths included opioid analgesics (75.2%); benzodiazepines (29.4%), antidepressants (17.6%); antiepileptic and antiparkinson drugs (7.8%); systemic and hematologic drugs (7.2%), and undetermined (8.4%). Nearly three-fourths (74.3%) of the medication-related deaths were deemed unintentional and 17.1% were suicides.

Among the overdose deaths that involved opioids, the most common medications taken concomitantly were benzodiazepines (30.1%), antidepressants (13.4%) and antiepileptic and antiparkinson agents (6.8%).

The team also looked at what fraction of overdose deaths involving other medications also involved opioids. They found opioids were implicated in 77.2% of overdose deaths that involved benzodiazepines; 65.5% of deaths in which antiepileptic and antiparkinson drugs also were implicated; 58% of deaths involving antipsychotics and neuroepileptics; and 50% of barbiturate-related deaths.

Among central nervous system and psychotherapeutic drugs, opioid analgesics were the drug class with the highest percentage of deaths in which no other drug class was involved: Nearly 30% of opioid analgesic–related deaths involved no other drugs. Benzodiazepines were involved in the smallest proportion of single-drug class deaths, with only 2.7% of benzodiazepine-related deaths involving no other drugs.

“The main take-away message from our work is that beyond the opioid analgesics, mental health medications are commonly involved in overdose deaths,” Dr. Jones told Pharmacy Practice News. “That really highlights the importance of screening for mental health or substance abuse disorders when a patient [is seen by a clinician].”

He noted that other studies have shown that patients with mental health disorders are at increased risk for an overdose death (J Clin Psychiatry 2010;71:491-496). They also are more likely to be prescribed higher doses of opioids, and also may be more likely to self-escalate the dose, said Dr. Jones. His team now intends to study the medication combinations that have been involved in drug overdose deaths over time.