While Louisville’s heroin epidemic shows no sign of stopping, fentanyl — a synthetic opioid up to 50 times more potent — has surpassed it as the leading cause of fatal drug overdoses that continue to dramatically increase locally, according to records provided by the Jefferson County Coroner’s Office.

Data from the local coroner’s office shows that 324 individuals died from an accidental drug overdose in 2016, which is a 47 percent increase from the 220 fatal overdoses in 2015 — a year in which Jefferson County also withstood a 31 percent increase from 2014, according to the Kentucky Office of Drug Control Policy.

Though nearly half of the fatal drug overdoses in 2015 involved heroin, this drug was only present in the toxicology reports of 30 percent who died from an overdose in 2016, and the total with heroin in their system actually decreased from 102 to 99 over that time. On the other hand, fentanyl or its derivatives went from being present in 26 fatal overdose victims in 2015 to 139 last year. That figure is not only more than five times higher, but the percentage of fentanyl-related overdose deaths went from 12 percent of the total fatalities in 2015 to 43 percent last year, far outpacing heroin or any other drug.

Another indicator that fentanyl has surpassed heroin as the deadliest drug in Louisville is the fact that overdose deaths that did not involve fentanyl actually decreased in 2016. While the total of heroin-related deaths also went down slightly in 2016, there was an even larger decrease in the number and percentage of victims whose toxicology report showed they had heroin in their system but not fentanyl — dropping from 93 in 2015 (42 percent of total deaths) to 68 in 2016 (21 percent of total deaths).

Statistics provided by Jefferson County Coroner

The data from the Jefferson County Coroner also shows the spike in fatal fentanyl overdoses was not spread evenly across 2016, but rather concentrated in several large bursts in which multiple victims died from the drug across several consecutive days, while at other points during the year, weeks would go by without a single instance.

Statistics provided by Jefferson County Coroner

For example, the deadliest stretch of fentanyl overdoses in 2016 occurred over a 30-day period from May 20 to June 18, when 44 individuals died. Multiple people died from a fentanyl-related overdose on 14 days during this stretch, with at least three people fatally overdosing on the drug in six of those days. On the other hand, in nearly half of the weeks during the year, either one person or no one overdosed with fentanyl in their system.

The next-deadliest stretch of fentanyl-related overdoses occurred in March — the same month that the Louisville Metro Department of Health and Wellness first sounded the alarm about the new threat of fentanyl. On March 14, the department issued a press release alerting the public to a dramatic increase in fatal overdoses over the past week, warning that heroin supplies were increasingly being cut with the more potent fentanyl. Over the span of 13 days in March, 17 people fatally overdosed with fentanyl in their system.

While Louisville made national headlines on Aug. 30 for having nearly 30 patients treated in hospitals on that day alone due to suspected heroin or fentanyl overdoses, there was only one fatal drug overdose that day, and the victim had only heroin in their toxicology screening. That same month a person fatally overdosed with the fentanyl derivative carfentanil — an elephant tranquilizer that is 100 times more powerful than fentanyl — the only known victim to test positive for the rare drug that is starting to pop up in the Ohio Valley region.

Though the initial warnings about fentanyl in Louisville indicated it was being cut into heroin supplies without the buyers’ knowledge, the coroner’s data shows that those who fatally overdose when using it typically do not also have heroin in their system, suggesting that most using the drug either take it alone or with drugs other than heroin. Both fentanyl and heroin were found in 31 fatal overdose victims, but 108 fatal overdose victims used fentanyl without heroin. Local and federal law enforcement suggest that people are increasingly using fentanyl that is manufactured within cocaine, methamphetamine and counterfeit painkiller pills. There also are increasing reports of fentanyl being stolen from hospitals, where the painkiller is sometimes given to terminally ill cancer patients.

Local experts have said initial reports from the first two months of 2017 suggest that this opioid epidemic of addiction, overdoses and fatalities is only escalating in Louisville. Overdose runs by Louisville EMS and the administering of the opioid overdose antidote naloxone by its personnel have reached record highs in recent months, while LMPD says that overdose deaths suspected of being heroin-related are well above the pace of early last year.