Between August 2010 and December 2012, two changes — introduction of an abuse-deterrent OxyContin and removal of propoxyphene (Darvon) from the marketplace — led to a 20 percent drop in the number of overdoses from prescription painkillers, say collaborating researchers at Boston Medical Center and Harvard Medical School. However, an increase in heroin overdoses more than offset the decline in prescription painkiller overdoses during this period.

OxyContin, introduced by Purdue Pharma in 1995, is a painkiller that provides up to 12 hours of relief. According to Forbes, the time-release formulation of Oxy (as it is commonly called), intended to reduce the risk of addiction, provided a measure of comfort to the doctors prescribing it. Since its introduction, though, prescription opioids including Oxy swiftly overtook both heroin and cocaine as the number-one cause of drug overdose deaths in the United States.

After more than a decade, Purdue Pharma designed a reformulated version of OxyContin to be resistant to crushing or dissolving — common methods for abuse. The Food and Drug Administration approved the reformulation in 2010. For the current study, then, the researchers posed a simple question: Did this new drug design have positive effects on abuse and overdose rates?

Unanticipated Consequence

To begin, the researchers analyzed claims reported to a national health insurer between Jan. 1, 2003, and Dec. 31, 2012. The claims covered 31.3 million commercially insured members between the ages of 18 and 64. Specifically, the researchers looked for potential effects following the introduction of abuse-deterrent OxyContin, an event that was closely trailed by the withdrawal of propoxyphene, another commonly abused painkiller, on Nov. 19, 2010.

What did the researchers discover? Two years later, total opioid dispensing decreased by 19 percent. Similarly, the estimated overdose rate attributed to prescription opioids decreased by 20 percent. Shockingly, though, heroin overdoses increased by 23 percent in the same period.

"Pharmaceutical market interventions may have value in combating the prescription opioid overdose epidemic," wrote the researchers in their published study, "but heroin overdose rates continue to increase." Oxy, according to both scientific and popular medial reports, has become the gateway drug to its fellow opioid, heroin. Apparently, Dr. Marc Larochelle, an assistant professor of medicine at Boston University School of Medicine and lead author of the new study, and his colleagues concur.

"Given the decreased supply of prescription opioids, those seeking out an opioid could be turning to heroin, which may partially explain the tremendous increase in heroin overdose deaths over the past few years, both locally and nationally," Larochelle said. Once again, it is the consequence no one saw coming that hurts most.

Source: Larochelle MR, Zhang F, Ross-Degnan D, Wharam F. Rates of Opioid Dispensing and Overdose After Introduction of Abuse-Deterrent Extended-Release Oxycodone and Withdrawal of Propoxyphene. JAMA. 2015.