The U.S. is in the midst of an opioid crisis. Deaths from prescription painkiller overdoses have quadrupled since 1999. To combat the epidemic, 49 states and Washington, D.C., have built computer systems intended to detect when people try to get multiple prescriptions, either for their own use or to sell illegally.

The prescription drug monitoring programs, or PDMPs, track patients who already have prescriptions for controlled substances and can alert prescribers if someone appears to be “doctor-shopping.” The problem? They often go neglected by physicians.

Now advocates want stricter laws that require doctors to use the databases. Currently just seven states mandate that prescribers check the systems before giving patients opioids in all circumstances. More require them to get patients' prescription history only if they suspect abuse. There's no reliable data on how often doctors use PDMPs, but evidence from such states as New York, Tennessee, and Kentucky show that they are used much more frequently when the law requires it.