[CATO] A study published last year by researchers at the University of Pennsylvania and Pennsylvania State University found that state Prescription Drug Monitoring Programs (PDMPs), a popular method used to drive down the opioid prescription rate, do not drive down opioid overdose death rates, but might have the unintended consequence of adding to them, by driving users to the underground market where dangerous drugs like fentanyl and heroin await them. Another study last October by a Purdue University researcher found that while PDMPs drove down the prescription rate of oxycodone, they significantly drove up the rate of heroin use.Yesterday the Annals of Internal Medicine published a systematic research review by Columbia University epidemiologist David Fink and others that drew the same conclusion. The authors stated, “Evidence that PDMP implementation either increases or decreases nonfatal or fatal overdoses is largely insufficient, as is evidence regarding positive associations between specific administrative features and successful programs.” They added, “implementation of PDMPs may have unintended negative outcomes—namely, increased rates of heroin-related overdose.”