The Cook County medical examiner’s office has confirmed the county’s first two deaths due to new analogs of the powerful opioid fentanyl — 10,000 times more potent than morphine and typically used in veterinary practices to immobilize large animals like elephants.

One was in Chicago, the other in Lake Zurich.

They’re among a growing number of deaths from fentanyl and fentanyl analogs.

On Sept. 10, a 46-year-old West Side man died from a lethal combination of fentanyl analogs including Carfentanil.

These “were not pharmaceutical-grade drugs like those administered by medical professionals for severe pain,” according to Dr. Ponni Arunkumar, the chief Cook County medical examiner. “Carfentanil is a fentanyl analog that is 10,000 times more potent than morphine, which is the active component of heroin. Carfentanil is used in veterinary practices to immobilize large animals.”

Toxicology testing has also shown that a 35-year-old Lake Zurich man who died June 8 suffered a 3-methylfentanyl overdose, the medical examiner’s office found.

“3-Methylfentanyl is also a fentanyl analog, and it is four times more potent than morphine,” according to Arunkumar.

Samples of street packaged fentanyl were displayed by the U.S. DEA at a news conference on their increasing threat in 2015. Deaths in Cook County from the opioids have skyrockets since then. | Sun-Times file photo

Samples of street packaged fentanyl were displayed by the U.S. DEA at a news conference on their increasing threat in 2015. Deaths in Cook County from the opioids have skyrockets since then. | Sun-Times file photo

“Fentanyl and fentanyl analogs, like Carfentanil, are very powerful drugs that are likely to be lethal,” Arunkumar said. “Just one dose can easily stop a person from breathing, causing immediate death.”

Carfentanil is an elephant tranquilizer, according to Dr. Steve Aks, emergency physician and toxicologist at Cook County Health & Hospitals System’s Stroger Hospital.

“It is not a drug that humans should be ingesting,” Aks said. “These high-potency opioids and opioid analogs are thousands of times stronger than street opioids like heroin and are far more likely to cause death.”

There have been 380 deaths so far in 2016 caused at least in part by fentanyl or fentanyl analogs, according to the medical examiner’s office. That number is likely to rise because it can take three months for test results to be finalized.

But it’s already a nearly 300 percent increase over last year, when 102 deaths were linked to fentanyl or fentanyl analogs, according to the medical examiner’s office. In 2014, there were only 20 such deaths in Cook County.

Medical examiners began testing for fentanyl routinely starting in June 2015 to keep up with national trends showing a spike in their use. Previously ,such tests were run at the discretion of a pathologist if the circumstance of the case — such as an unknown substance found in a decedent — called for it.

The most common such opioids found in overdose victims in Cook County have been furanyl fentanyl and a precursor/metabolite of fentanyl called despropionyl fentanyl (4-ANPP), according to the medical examiner’s office.