Fatal overdoses from benzodiazepines—sedatives sold under brand names such as Xanax, Valium and Ativan—are on the rise, a new study finds.

Overdoses from benzodiazepines accounted for 31 percent of the almost 23,000 deaths from prescription drug overdoses in the United States in 2013, according to HealthDay.

“As more benzodiazepines were prescribed, more people have died from overdoses involving these drugs,” said study author Dr. Joanna Starrels of Albert Einstein College of Medicine. “In 2013, more than 5 percent of American adults filled prescriptions for benzodiazepines. And the overdose death rate increased more than four times from 1996 to 2013.”

She noted while there has been a large public health response to the epidemic of prescription opioid use, addiction and overdose, there has not been much response to the increase in prescription benzodiazepine deaths.

Dr. Starrels said the rate of deaths from benzodiazepines is still lower than deaths from opioid overdoses, but noted benzodiazepine deaths also involve opioids in about 75 percent of cases. She said benzodiazepines can slow breathing, “particularly when taken with alcohol or narcotics such as OxyContin or heroin.”

Starrels and colleagues used data that tracks drug prescriptions and drug overdoses. They found the number of adults who used benzodiazepines rose from 8.1 million prescriptions in 1996, to 13.5 million in 2013—a 67 percent increase. The quantity of filled prescriptions more than doubled during that period.

The overdose death rate for benzodiazepines rose from 0.58 deaths per 100,000 in 1996 to more than 3 deaths per 100,000 in 2013—a more than fivefold increase.

While the overall number of overdose deaths has leveled off since 2010, the rate continues to increase among adults over 65, as well as among blacks and Hispanics.

The study appears in the American Journal of Public Health.