TUESDAY, Jan. 22, 2019 (HealthDay News) -- Although the U.S. opioid epidemic dates back more than a decade, only 6 percent of treatment centers in 2016 offered the three medications approved to treat opioid addiction, new research reveals.

And only about a third offered even one of the three recommended drugs, the study found.

"The country is dealing with an opioid overdose death epidemic," said study lead author Dr. Ramin Mojtabai, a professor of mental health at the Johns Hopkins School of Public Health in Baltimore.

"Attention to medication treatment for opioid use disorders can help to curb this epidemic," along with distribution of opioid-blocking naloxone kits to prevent OD deaths, he said.

Buprenorphine, naltrexone and methadone are approved by the U.S. Food and Drug Administration for long-term treatment of opioid use disorder, including addiction to prescription painkillers and heroin. But many centers still rely on talk therapy to promote abstinence.

Mojtabai and his team analyzed national surveys of 10,000 outpatient centers conducted by the U.S. Substance Abuse and Mental Health Services Administration (SAMHSA) between 2007 and 2016.

On the upside, just 20 percent of facilities offered at least one opioid treatment medication in 2007, but that figure was 36 percent in 2016.

However, "only a small fraction offered all three," said Mojtabai.

Methadone and buprenorphine are so-called agonists that attach to opioid receptors in the brain and reduce craving, Mojtabai explained. Naltrexone, an extended-release antagonist, is injected monthly to block opioid receptors and curtail any "high."

The findings didn't surprise Lindsey Vuolo, associate director of health law and policy at the Center on Addiction in New York City.

"We know that only one to two in 10 people receive any treatment for their substance use disorder, and that only a fraction of the people receiving addiction treatment receive these medications," Vuolo said.

These medications help, she added.

"Overall, approximately 50 percent of patients who receive medications for opioid addiction are successfully treated, while less than 10 percent of patients are successfully treated without these medications," said Vuolo, who was not involved in the study.

According to the U.S. Centers for Disease Control and Prevention, drug overdose deaths involving opioids topped 47,000 in 2017.

Whether treatment options have improved since 2016, when the study ended, isn't known.

"It is quite possible that with growing attention and funding, facilities are doing a better job at providing these vital treatments in more recent years," Mojtabai said. He mentioned the launch of new SAMHSA opioid crisis grants as an example of progress.

But Vuolo cautioned that while treatment access has increased in states such as Rhode Island and Vermont, growth has unfolded unevenly across the country.

"The number of people receiving treatment has not changed significantly, even in light of the unrelenting opioid epidemic," she said.

"I don't think research will show significant changes between 2016 and 2019 on a national scale," Vuolo noted.

Mojtabai believes "there are probably multiple reasons" why opioid medication access has been limited.

"State Medicaid programs vary with regard to covering these medications," he said. "Also, facilities need to have providers that can prescribe buprenorphine. Hiring such providers is costly."

It's also possible there still are concerns about using medications to treat drug abuse, despite strong evidence of their effectiveness and safety, Mojtabai added.

Vuolo said changes in clinical rules since 2016 have expanded the pool of caregivers who can prescribe opioid treatments. In addition, 254 new opioid treatment programs opened between 2014 and 2018.

But she characterized such developments as "pretty small, incremental improvements."

The "lack of access to these medications is one of the major reasons we continue to see so many people dying from opioid overdoses," Vuolo said.

The study findings are in the January issue of Health Affairs.

More information

The U.S. National Institute on Drug Abuse has more on the U.S. opioid crisis.