Friday, October 12, 2012

Opioid Poisoning Risk Less Than For Other Drugs

Drug RiskWith pharmaceuticals becoming increasingly accessible, poisoning and overdose have become rising concerns in the United States and throughout the world, particularly involving opioid analgesics. Now, a newly published study from the University of Rochester Medical Center reports that nonopioid analgesics and psychotropic agents are more likely to be associated with drug poisoning overdose than opioid analgesics [Wiegand et al. 2012].

Writing in an early online edition of the Journal of Medical Toxicology, the researchers examined data from 2011 in the 2nd annual report of the Toxicology Investigators Consortium, or ToxIC. This group — created by the American College of Medical Toxicology — has developed a real-time surveillance system for determining trends among all cases evaluated by medical toxicologists. The 2011 database included 10,392 cases from 28 sites encompassing 49 specific institutions; 53% of the included patients had been sent to emergency departments.

The most common reason patients were sent to emergency rooms, representing 48% of those cases, was due to pharmaceutical overdose, including 37% intentional self-harm and 11% accidental exposure. The most common classes of involved agents were sedative-hypnotics (23% of cases), nonopioid analgesics (21%), opioids (17%), antidepressants (16%), stimulants/sympathomimetics (12%), and ethanol (8%).

There were 35 deaths recorded in this Registry during 2011, and the most frequently involved agents — including when reported as sole agent or in combination with other agents — were nonopioid analgesics (acetaminophen, aspirin, NSAIDs) and opioids, accounting for 8 and 10 deaths, respectively. Of the 10 opioid-related deaths, oxycodone was reported in 6 and heroin in 3. Acetaminophen was the most common single drug reported overall, identified in all 8 of the deaths attributed to nonopioid analgesics.

Some significant and alarming trends also were identified. The designer psychoactive drug “bath salts” was responsible for a large increase in stimulant/sympathomimetic-related cases reported to the Registry in 2011, with overall numbers doubling from 6% of all Registry entries in 2010 to 12% in 2011. Entries involving other psychoactive drugs of abuse also increased two-fold from 2010 to 2011, primarily due to increasing frequency of synthetic cannabinoid-related intoxications.

The authors observe that much of the current concerns about medication abuse have centered on prescription opioids, which are indeed of concern regarding morbidity and mortality related to overdose poisoning. However, the data reported in their study suggest that emphasis also should be placed on other analgesics and prescription medications, as well as illicit substances of abuse.

COMMENTARY: The ToxIC Case Registry continues to grow and is an important research tool for identifying and characterizing confirmed cases of significant toxicity and as a surveillance system to identify current trends. It is a robust multicenter database; however, like all such observational approaches it presents a limited epidemiological snapshot of the real world and there may be an under- or over-reporting of cases and regional differences in trends.

Despite the limitations, data in this report suggests several points for further consideration:

  • An unbalanced focus on opioid analgesic harms neglects other medications, as well as many illicit substances, that have greater or comparable risk for misuse, abuse, and overdose. In particular, nonopioid analgesics confer a 24% greater risk of poisoning and overdose than opioids.

  • There is an implication that a shift from opioids to other analgesics, as well as adjunctive medications, for treating pain may incur significant harms in persons with pain. The high rate of acetaminophen involvement in poisonings and deaths seems particularly troublesome.

  • Intentional self-harm (suicide attempt) using pharmaceuticals, representing more than a third of emergency department cases, is of great concern; although it is not known if this relates more to mental health issues or the undertreatment of pain.

  • Increases in the use of designer psychoactive drugs (eg, bath salts, synthetic cannabinoids), as well as the ongoing presence of drugs like heroin, suggest that substance abuse problems in the population continue to rage out of control — and prescription opioids are only one part of a much larger scenario.

In regard to the last point, the extensive catalog of licit and illicit substances with abuse, addiction, and overdose potential that are available today is somewhat astounding. For example, the U.S. Drug Enforcement Agency (DEA) provides a comprehensive 51 pages of fact sheets, covering amphetamines to steroids and everything in between [PDF here]. The U.S. National Institute on Drug Abuse (NIDA) also offers a considerable amount of important and helpful information [here].

REFERENCE: Wiegand TJ, Wax PM, Schwartz T, et al. The Toxicology Investigators Consortium Case Registry—The 2011 Experience. J Med Tox. 2012(Oct); online ahead of print [abstract].

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