Doctors should be more aware of their patients’ potential use of prescription drugs purchased through illegitimate, or “rogue,” online pharmacies. That’s according to a commentary published Monday in the Annals of Internal Medicine that calls attention to the dangerous presence of Internet-based pharmacies selling prescription drugs without prescriptions.

These Internet-based outfits have for years sold prescription medications to people who present no prescription at all or who fax in a “prescription” that may or may not be legitimate. Many simply have customers complete an online questionnaire, on the basis of which some mysterious physician issues a prescription for the desired drug. The authors cite research showing that “U.S. rates of abuse of controlled prescription medications exceed those of all illicit drugs combined except marijuana.”

The authors note that “rogue” pharmacies are tricky to pin down because they pop up online and disappear again with alarming speed, making it hard to identify or take action against them. When a physical location can be ascertained, it’s often outside U.S. jurisdiction.

Nor are their customers easy to peg: People who buy drugs this way don’t usually fit the conventional illegal drug-user mold, the commentary notes, and it’s just as hard to track the customers as it is to find the pharmacies.

The commentary suggests that combating the rogue pharmacy phenomenon would require the combined efforts of federal, state and private forces to better identify illegitimate pharmacies, enforce existing laws and crack down on perpetrators. But that full-out action would be extremely costly, the authors acknowledge.

That’s why doctors need to step up their game, the article suggests, by becoming more aware of the phenomenon and asking patients — even, or especially, those they’d never suspect of abusing prescription drugs — about whether they buy medications from rogue pharmacies.

If you were among those who buy drugs this way, would you admit it to your doctor?