[T]he selection of OxyContin as a primary drug of abuse decreased from 35.6% of respondents before the release of the abuse-deterrent formulation to just 12.8% 21 months later (P<0.001). Simultaneously, selection of hydrocodone and other oxycodone agents increased slightly, whereas for other opioids, including high-potency fentanyl and hydromorphone, selection rose markedly, from 20.1% to 32.3% (P=0.005). Of all opioids used to “get high in the past 30 days at least once," OxyContin fell from 47.4% of respondents to 30.0% (P<0.001), whereas heroin use nearly doubled.The idea with tamper-resistant formulation of OxyContin is that it's difficult crush pills for snorting or put them into solution for injecting (though users quickly found ways to do so by further processing the pills). What the authors have shown is that, at least in their small sample, this seems to have worked: significantly fewer people are using OxyContin to get high. What they haven't found is any reduction in overall opioid use.
And the kinds of opioid use people are turning to in lieu of OxyContin is what makes this a public health failure and an overdose concern: people appear to largely be turning to much more dangerous drugs. Heroin use, of course, carries risks associated with impurities in the cut, which in some cases may contribute to vein damage, infections, or a variety of toxic effects. The variable quality of street heroin, moreover, increases the likelihood that users' tolerance will fluctuate, thereby increasing overdose risk. Increased use of high potency opioids such as fentanyl is an obvious overdose risk, and indeed has been linked to spikes in overdose mortality in a number of locations.