Our analysis showed that the implementation of a province-wide centralized prescription network was associated with large, immediate and sustained reductions in filled prescriptions for opioid analgesics and benzodiazepines deemed inappropriate by our definition. These findings provide empirical evidence that centralized prescription networks can reduce inappropriate prescribing and dispensing of prescriptions by offering health care professionals real-time access to prescription data. Physicians did not have access to PharmaNet when it was first introduced; consequently, the reductions observed in our study likely reflect the availability of real-time prescription information to front-line pharmacists.
Although the effectiveness of centralized systems may vary across jurisdictions, such differences are likely irrelevant from a policy standpoint, because even modest reductions in inappropriate prescriptions are clinically meaningful. If our findings can be generalized to other jurisdictions, we estimate that such networks could eliminate millions of inappropriate filled prescriptions in the United States and Canada annually.
Some limitations of our study merit emphasis. Defining filled prescriptions as inappropriate with the use of claims data is not straightforward. We purposefully employed a rigid definition so that our estimates of system impact would be conservative. Our definition may have resulted in some appropriate prescriptions being classified as inappropriate. However, it excluded many other inappropriate prescriptions, including those characterized by smaller quantities (< 30 tablets), longer intervals between prescriptions, and provenance from either a single prescriber or a single pharmacy. Our definition also excluded situations involving proximate prescriptions for different drugs, such as oxycodone and hydromorphone, and lorazepam and alprazolam. Consequently, our results almost certainly underestimate the ability of such networks to reduce inappropriate prescribing and dispensing of prescriptions. We used a 7-day window rather than a longer follow-up window to avoid classifying appropriate prescriptions as inappropriate. Inherent to this choice was an assumption that the probability of accurately identifying an inappropriate prescription decreased as more time elapsed between prescriptions.
Some pharmacies started using PharmaNet before the summer of 1995, when most pharmacies went online. This limitation could only have attenuated any observed effect of PharmaNet.
The effect of PharmaNet on benzodiazepine prescriptions may have been augmented by an educational letter on sleep management mailed to physicians and pharmacists in BC in January 1996.10
However, a previous evaluation of the letter suggests it was associated with a nonsignificant reduction in de novo prescribing of benzodiazepines,11
and no such letter was issued for opioids.
Finally, our analysis reflects data from a natural experiment that took place 17 years ago. However, the data are of high quality and are particularly relevant in light of prevailing concerns regarding the abuse and diversion of prescription drugs.12
The implementation of a centralized prescription network was associated with a dramatic reduction in potentially inappropriate filled prescriptions for opioids and benzodiazepines. We speculate that wider implementation of such networks could substantially reduce the costs and harms associated with misuse of prescription drugs.