A new study finds buprenorphine is prescribed to fewer than half of Americans treated for opioid addiction. Buprenorphine is potentially lifesaving for people with opioid use disorder, according to the researchers at Washington University School of Medicine.

The researchers evaluated health insurance data from about 180,000 people treated for opioid use disorder from 2011 to 2016. They found just 47% were prescribed buprenorphine. The rate was only 30% among people who had opioid use disorder and also used other substances such as alcohol, methamphetamine, benzodiazepines or cocaine, HealthDay reports.

“This is equivalent to giving those with advanced cancer a less aggressive treatment,” senior investigator Laura J. Bierut, M.D., said in a news release. “It seems obvious to many of us that we should be giving the most aggressive and effective treatments to those who are most seriously ill.”

“Buprenorphine appears to be a safe opioid,” added study co-author Kevin Xu, M.D. “It’s specifically designed to be different from other opioid drugs in that it won’t cause a user to stop breathing, which pretty much every other type of opioid will do. That means it can be taken safely at home, which is very helpful, even essential, to recovery.”