City and state health directors are urging the Food and Drug Administration (FDA) to put warning labels on powerful painkillers that can be fatal when taken with other drugs.

In a petition, a group of health directors led by Dr. Leana Wen, Baltimore’s health commissioner, and Dr. Nicole Alexander-Scott, Rhode Island’s health director, call for “black box warning” labels on opioids and benzodiazepines.

{mosads}“Existing warnings about the concurrent use of opioids and benzodiazepines are inconsistent, infrequent, and insufficient,” Alexander-Scott said in a statement. “The FDA should act swiftly on the clear scientific evidence and add black box warnings to both classes of medication.”

The petition, signed by 28 other city and state health directors, also calls for guidelines to specifically warn patients about the risks of combining opioids and benzodiazepines. Opioids are often prescribed to treat a patient’s pain, while benzodiazepines are often prescribed to treat associated symptoms like anxiety and sleep disorders.

According to a second petition for the public, nearly 1 in 3 unintentional overdose deaths from prescription opioids also involved benzodiazepines.

“The science is clear: combining opioids with benzodiazepines is dangerous and is fueling the overdose epidemic,” the petition says. “A black box warning will help to educate both patients and clinicians about this potentially lethal drug interaction.”