Drugstore chain CVS announced Wednesday that it is helping crack down on “pill mill” doctors who prescribe high levels of high-risk drugs. The company outlined its initiative in the New England Journal of Medicine, and said it found 42 prescribing outliers among its almost 1 million prescribing healthcare professionals after surveying data from March 2010 through January 2012. CVS said it has contacted the outliers and cut off supplies for those who were unresponsive or provided inadequate information for the prescribing patterns. The company said three of the 26 “non responsive” clinicians have requested their CVS prescribing privileges be restored, nine months after the drugstore chain ended the relationship.

The chain’s focus was on prescriptions including the painkillers hydrocodone and oxycodone, synthetic opioid methadone, anti-anxiety medication alprazolam, and the muscle relaxant carisoprodol.

CVS said its extensive reach gives retailers of its size “the advantage of aggregated information on all prescriptions filled at the chain,” and that pharmacists “have an ethical duty . . . to ensure that a prescription for a controlled substance is appropriate.”

An ongoing Reuters poll noted last week that one in every 10 Americans say they’ve taken prescription drugs handed off by a third-party, with around 25% of them telling Reuters it was to get high. 

Concern over high prescription levels has been an ongoing concern, particularly among drugs on the Drug Enforcement Agency’s list of controlled substances: Health and Human Services’ Office of the Inspector General released a report in June that found high prescription rates of drugs on its Schedules I and II among Medicare Part D members. This was in addition to the OIG’s previous findings that refills were being offered and filled for Schedule II drugs, violating federal law.

This is addition to regulatory efforts to give patent precedence to opioid medications that are harder to abuse than their predecessors, as was the case when the FDA said generic oxycontin was not going to hit the marketplace because Purdue Pharma’s new version was more abuse-resistant. This is contrast to Endo, which lost its case against Opana ER generics because the regulator said the later iteration—also called Opana ER—was not difficult to manipulate, compared with the previous version.

CVS’s jump into prescription limits, however, is not the company’s first encounter with limits. The DEA slapped the company with an $11 million fine in April for alleged violations of the Controlled Substances Act in its Oklahoma stores. In 2012 the DEA revoked the ability of two Miami CVS stores to dispense controlled substances. It was the first time the agency revoked registrants of a national chain. Bloomberg notes Walgreen Co. paid an $80 million settlement over allegations that its record-keeping violations “allowed highly addictive drugs to reach abusers and be sold illegally.”

“Our program is certainly not a comprehensive solution, but it provides some sense of the kind of inappropriate prescribing that is going on in our health system,” CVS wrote in its NEJM article.