The figures are tentative, but they show that Ohio might have turned the corner in combating drug overdose deaths.

The Buckeye state's drop of 21.4 percent was the biggest in the nation in a new provisional count of fatal overdoses from July 2017 through June 2018 released last week by the Centers for Disease Control and Prevention.

Separately, Ohio Department of Health preliminary data show a 34 percent decline from January to June 2018, from the same six months in 2017, down to 1,812 overdose deaths statewide.

And records for all of 2018 from several large counties contacted by The Dispatch show decreases approaching 50 percent — although Franklin County does not appear to be sharing that downward trend.

"The news is encouraging and we are cautiously optimistic, but it's not the time to take our foot off the gas," said Mark Hurst, director of the Ohio Department of Mental Health and Addiction Services, noting that the data are still preliminary.

Hurst said several efforts likely contributed to the decline, including education and prevention, increased use of medication-assisted treatment, and the availability of overdose-reversing medication like naloxone, which is available at most pharmacies without a prescription and carried by many emergency responders. In addition, strict state oversight has prompted a reduction in prescription opioids, Hurst said.

Ohio reported a record 4,854 drug overdose deaths in 2017, a 20 percent jump over 2016’s toll and the eighth year of increases in a row. The state had the nation's second-highest per capita drug death rate, next to West Virginia, in 2017, the CDC reported. Ohio health officials will release a final count for 2018 this summer; county coroners are given six months to complete their investigations and submit death certificates to the state.

The new CDC figures show drug deaths peaking across the country in September 2017 and starting a slow descent.

One key factor for the apparent sharp decline in Ohio drug deaths: The almost total disappearance of deadly carfentanil, which often was mixed with cocaine and sold to unsuspecting users.

"The reason overdose deaths have fallen sharply in Ohio can be attributed to a singular cause: Carfentanil has nearly vanished from Ohio’s illegal drug supply," said an analysis by Harm Reduction Ohio, a nonprofit based in Granville founded by Dennis Cauchon, who was a national reporter for USA Today before starting the organization in 2016.

"It’s important to understand that carfentanil was responsible for essentially the entire surge in overdose deaths between the mid-2016 and mid-2017, a death spike that pushed Ohio from No. 5 in overdose death rates to No. 2," Cauchon said in the analysis. Carfentanil was relatively unique to Ohio; its role in overdose deaths was 21 times that of other states studied by the CDC.

"For whatever reason, the presence of carfentanil peaked in the spring of 2017 and fell sharply and fast. The drug left Ohio nearly as quickly as it came," said the nonprofit, which estimates the substance killed about 2,000 Ohioans in two years.

Cuyahoga County medical examiner Thomas P. Gilson also noted the steep decline in deaths from carfentanil — from 191 in 2017 to 24 last year — possibly because of its toxic reputation.

Overall, the county’s drug death total fell 23 percent in 2018, from 727 to 560, preliminary figures from Gilson show.

In Summit County, drug deaths are down by half. The county medical examiner has confirmed 108 overdose deaths in 2018 with another 25 presumed but still under review. That’s down from 271 fatal overdoses in 2017.

In Hamilton County, officials say they had 440 suspected drug overdoses in 2018, down from 567 confirmed deaths in 2017.

Hard-hit Montgomery County, regarded by some as the epicenter of the nation's opioid epidemic, recorded a 48 percent drop in drug deaths last year.

Officials in the county that contains Dayton say preliminary findings show 294 drug overdoses in 2018, down from 566 in 2017, or 98 for every 100,000 residents and the highest rate in the state.

Last week, Gov. Mike DeWine made Dayton the first stop on a statewide listening tour to develop a plan to tackle Ohio's drug problem.

Mayor Nan Whaley, noting that recovery often takes five years, says the city's pioneering work is now paying off: It was among the first to declare an emergency over the drug crisis, to equip first responders with overdose-reversing naloxone and to set up a needle exchange.

"It takes a long time to be in recovery, and relapses are very common," she said. "So what we did years ago is now bearing fruit."

A united, countywide effort also was crucial, Whaley said, with a Community Overdose Action Team of more than 50 public and private organizations dealing with education, prevention, treatment and recovery.

Cuyahoga County Executive Armond Budish also urged caution: “We’re still losing way, way too many lives, and we cannot afford to relax our efforts.”