The reason for the dip can be mostly attributed to the tighter refill controls that schedule II drugs have. Whereas physicians were able to prescribe several refills at a time when hydrocodone combinations products were under schedule III, patients were required to return to the physician for each refill. In total, refills accounted for 73.7% of the decline, and they were eliminated by March 2015.

Interestingly, in the 12 months after the rescheduling, non-hydrocodone combination analgesics increased by 4.9%, though this is not considered to have significantly affected the total number of opioid analgesics dispensed. Using a model of linear regression analysis the study’s authors assert that the reductions in dispensed hydrocodone combination product prescriptions and tablets were substantially greater than would have been predicted in the absence of rescheduling. Bearing in mind how the numbers had already been on a slow decline, the author of the study deduced that the rescheduling resulted in an overall reduction of 14,360,378 (95% CI, 14,037,780–14,682,876) opioid prescriptions, and 750,095,774 (95% CI, 733,245,286–766,946,262) opioid tablets dispensed in the 12 months after rescheduling.

The numbers on record show a total of 26.3 million actual fewer prescriptions and 1.1 billion fewer tablets dispensed, in the 12 months after rescheduling. The only healthcare specialists who increased prescriptions during this period were pain specialists. Surgeons and primary care physicians showed the biggest decrease in allotted prescriptions, at 38.4% and 22.9% less, respectively.