CHARLESTON, W.Va. (AP) — Fatal overdoses linked to a powerful opioid nearly tripled in West Virginia last year.

Overdoses caused by fentanyl increased from 55 deaths in 2014 to 154 deaths last year, The Charleston Gazette-Mail reported.

The drug is an opioid that is sometimes laced with heroin and is stronger than prescription morphine. Hospitals often use it to put patients under for surgery.

West Virginia’s Bureau of Public Health commissioner Dr. Rahul Gupta says people can overdose and die more quickly with fentanyl.

“With fentanyl, it really acts quickly,” he said. “It’s a race against time to begin with, and when somebody’s dying because of an extremely potent substance, they’re going to be on the losing end of that race.”

Kanawha and Cabell counties had the most fentanyl-related deaths with 33 each. Berkeley County reported 15 fentanyl-related fatalities last year.

West Virginia has the highest drug overdose death rate in the nation. According to the state Health Statistics Center, at last count, 643 people died of drug overdoses in West Virginia in 2015. That number could increase as death reports from December continue to come in.

“The numbers are only going to get higher,” Gupta said.