Drug overdose deaths last year dropped for the first time in nearly three decades, according to a report this week from the Centers for Disease Control and Prevention.

The provisional data, still subject to change when final number are released later this year, show overdose deaths fell 5% in 2018, the first major decline during an addiction epidemic that has claimed tens of thousands of people this decade.

"The latest provisional data on overdose deaths show that America’s united efforts to curb opioid use disorder and addiction are working," Health and Human Services Secretary Alex Azar said in a statement. "Lives are being saved, and we’re beginning to win the fight against this crisis."

'People are dying of opioid overdose not knowing they have taken opioids'

While the drop is encouraging, experts say more than 68,000 deaths last year from drug overdoses remains a significant public health challenge.

"It's great that it's moving in the right direction," says Adam Leventhal, director of the University of Southern California's Institute for Addiction Science. "It's important that the public and policymakers recognize that the addiction crisis is unfortunately still alive and well. It's just shifting."

Prescription opioid painkillers, long blamed as the root of the crisis, are fading as a cause of drug overdose deaths. The CDC reported 12,757 overdose deaths from prescription painkillers in 2018, down from 14,926 deaths in 2017. Four other drug categories – methampetamine and other stimulants, cocaine, heroin and fentanyl – each caused more fatal overdoses last year than opioids such as oxycodone and Vicodin, the report said.

Fentanyl, a powerful synthetic opioid often sold as a street drug, surpassed prescription opioids in 2015 as the most lethal overdose substance and now is linked to nearly three times as many deaths. Nearly 32,000 overdose deaths last year involved fentanyl. In 2014, it was detected in fewer than 6,000 fatal overdoses.

Although the data attributes individual drug categories to deaths based on a coding system, overdoses increasingly include multiple substances.

Dr. Joshua Sharfstein, a former health secretary of Maryland and health commissioner of Baltimore, said that this new phase of the addiction epidemic is creating new challenges.

"A major concern is people are dying of opioid overdose not knowing they have taken opioids," said Sharfstein, vice dean at Johns Hopkins Bloomberg School of Public Health. "They think they are getting cocaine or they think they are getting methamphetamine. People might not have Narcan handy because why would they need it?"

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The federal government and state health departments have spent millions to purchase the opioid overdose reversal drug naloxone – or Narcan, the brand name for the nasal spray version. Naloxone reverses an opioid overdose if administered in time, but it does not counteract other drugs such as cocaine and methamphetamine.

The federal government also has sought to expand access to medication-assisted treatment drugs buprenorphine, naltrexone and methadone to wean people off of opioids.

'The addiction crisis in America is not solved'

There's been a national push to raise awareness among both doctors and patients about the potential harm of inappropriate prescribing. Total opioid prescribing has declined since 2012. The CDC issued an influential chronic pain guideline in 2016 to inform the public about appropriate prescribing.

But in a New England Journal of Medicine editorial last month, a panel of experts cited examples such as inflexible thresholds on dosages, abrupt tapering and misapplication of the guideline for people with cancer, sickle cell disease or recovering from surgery.

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Leventhal, of USC, said that the addiction crisis has shifted to a more complex era.

"The addiction crisis in America is not solved," Leventhal said. "It has morphed into a polysubstance use crisis. Something we need to be really concerned about is the increase in stimulant-related deaths, including cocaine, methamphetamine and other amphetamine derivatives."