Overdose deaths from prescription opioids in Colorado likely dropped last year to their lowest level in six years, but the state also saw a possibly connected increase in heroin and cocaine overdoses, according to preliminary numbers from Colorado’s Health Department.

Overall, the total number of opiate deaths — meaning deaths from both prescription painkillers like fentanyl or from illegal opiates like heroin — fell by about 6 percent, from 472 deaths in 2015 to 442 deaths in 2016. That marked a rare yearly downturn in opiate deaths, which have been climbing year-over-year in Colorado since at least 2000, with a couple other exceptions.

The biggest gains were made in reducing the number of deaths from traditional opioid painkillers like oxycodone and hydrocodone, which are sometimes called “natural” prescription opioids. Those deaths declined in 2016 by roughly 27 percent, from 259 to 188, according to the preliminary numbers.

Colorado has long been among the nation’s leaders in prescription drug abuse, and Dr. Larry Wolk, the executive director of the Colorado Department of Public Health and Environment, said the gains in preventing prescription overdose deaths mean Colorado has moved to somewhere in the middle of the pack nationally.

“So it’s definitely moving in the right direction,” he said.

For the improvement, Wolk credited the state’s campaigns to better monitor painkiller prescriptions and to provide easier disposal for unused medication. But he also called reducing prescription overdose deaths the “low-hanging fruit” of the opiate puzzle. And the increase in heroin deaths shows why.

Wolk said it is likely the prescription drug crackdown pushed some opiate users to heroin or other illegal drugs — though he doesn’t have all the information yet to say so conclusively. Heroin deaths in 2016 grew by 23 percent, from 160 to 197, according to preliminary figures. Deaths from cocaine overdose jumped by more than 50 percent, to 93.

Because the 2016 numbers are preliminary, they could still change before being finalized in the coming months. Health researchers also aren’t yet able to calculate death rates for 2016, which would show how the raw numbers compare to Colorado’s rising population.

Wolk said the state — through the Colorado Consortium for Prescription Drug Abuse Prevention — is now bringing together health and law enforcement officials to fight heroin deaths. He said the group could issue an initial report in the coming weeks.

“We know we have a problem,” Wolk said. “… Now we really have to turn our attention to the harder piece.”