Recent changes in the prescription drug market may have helped curb abuse of a class of prescription drugs known as opioids, but it may have also fueled a comparable rise in heroin use, according to an analysis released Monday.
Researchers examining insurance data over the course of about a decade found that the introduction of a special form of the branded opioid OxyContin that's harder to abuse, and the withdrawal from the market of another widely abused opioid in the same year, both coincided with drops in the amount of opium-containing drugs prescribed and the number of overdoses suffered by abusers.
Marc Larochelle and his colleagues at Boston Medical Center and Harvard Medical School evaluated insurance records for 31 million people from 2003-12 for patterns in abuse before and after the market changes were made. They focused only on commercial insurance policyholders, a group of people typically thought to be low-risk for substance abuse, Larochelle said.
The team publishes its findings Monday in the journal JAMA Internal Medicine.
Previous research had found that prescription opioid sales quadrupled between 1999 and 2010, and the number of overdoses rose in proportion. Those drugs include hydrocodone (sometimes sold as Vicodin), oxycodone (sometimes sold as Percocet and OxyContin) and others.
Two forces were major contributors to those rises, according to the study. A more potent OxyContin pill formulated to release slowly was particularly popular with abusers, who could "bypass" the extended release mechanism by crushing the pills and snorting the powder, the study said.
The second source was proproxyphene (sometimes branded as Darvocet or Darvon), a weak opioid that was originally compared to aspirin when it was introduced in the 1970s. Over the years, the drug grew into one of the most commonly abused opioids.
In the course of a few months in 2010, both problems found solutions: Manufacturers stopped making proproxyphene, and OxyContin manufacturer Purdue Pharma developed a plastic-encased "abuse-deterrent" form of the pill that was difficult to chew or crush into powder.
Within two years of those changes, prescription opioid overdoses dropped by 20 percent, and pill use overall was 19 percent lower than expectations.
Privately held Purdue said in a statement to CNBC that the current study is in agreement with its own findings that the new form of OxyContin is harder to abuse.
"This study parallels other independent and internal research that shows reformulated OxyContin is associated with a reduction in abuse," the company said. "We agree with the FDA, the U.S. Drug Enforcement Administration, the White House Office of National Drug Control Policy and many federal and state policymakers that abuse-deterrent formulations are a valuable public-health tool that must be part of any comprehensive approach to (combating) prescription drug abuse."
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Despite a reduction in U.S. abuse of prescriptions, however, heroin overdose rates rose 23 percent over the same period, suggesting a number of pill addicts turned to street drugs. The Boston Medical Center/Harvard team could not say for sure how much the rise of heroin was linked directly to the decline in prescription abuse. Heroin use was already on the rise by 2010, but the rate of increase accelerated after OxyContin was reformulated, Larochelle said.
"We aren't the first people to note that connection, and it is maybe not surprising," he said. "If you take away a drug, it is not going to cure an addiction, so they are likely to seek out an alternative medicine to meet that."
Heroin may have been that drug of choice because of its lower cost and availability.
"I have treated patients who have said they never would have started using heroin if they had not started with pills," Larochelle said.
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But the new study offers some evidence that doctors may be able to prescribe tamper-resistant OxyContin without as much fear that the drug will be abused.
"I would argue that this is only one part of a comprehensive strategy," Larochelle said. "I think we need other efforts really focused on identifying and treating substance-abuse disorders."
Purdue Pharma pleaded guilty in 2007 to federal charges that it misled the public about the addictive risks of OxyContin. The company agreed to pay more than $600 million in fines and other payments.
Correction: An earlier version of this article incorrectly named one of the institutions involved in the research.