The rule would effect an estimated 1.6 million Medicare beneficiaries who currently have prescriptions above that threshold. And it would prevent millions more from receiving prescriptions in the future.

The rule has plenty of critics, who say that it's a one-size-fits-all regulation that will come at the cost of patients dealing with severe pain.

In addition, some doctors say that such an abrupt change could be disastrous for many patients who are dealing with opioid addiction. They acknowledge that many patients are the victims of inappropriate opioid prescriptions in the past, but they argue that simply yanking away the drugs at this point would be unproductive.

"The decision to taper opioids should be based on whether the benefits for pain and function outweigh the harm for that patient," Dr. Joanna L. Starrels, a professor at Albert Einstein College of Medicine who studies opioids, tells the New York Times. "That takes a lot of clinical judgment. It's individualized and nuanced. We can't codify it with an arbitrary threshold." Treatment experts say that patients who have been on opioids for years should be encouraged to switch to less powerful forms of pain relief, such as ibuprofen. But they argue that that often takes counseling and a gradual reduction in opioid use. A sudden denial from a pharmacist could lead to disastrous results, including patients seeking out drugs illegally. In addition, a dosage that would be considered strong for a smaller person might be appropriate for a much larger patient.

In the long-term, the good news is that opioid prescriptions have been in decline since the beginning of the decade. The bad news is that there are still millions of Americans dealing with the consequences of over-prescribing.