A drug that some addicts have adopted as a replacement for OxyContin is slowly having an impact in the southwestern Ontario city of Sarnia, and at least one resident whose wife died from a Fentanyl overdose says he's speaking out to prevent other deaths.

Police say Fentanyl is becoming a killer street drug in Sarnia, which has a population of about 72,000.

They say two people died of Fentanyl overdoses last year. This year, one other person has died and two people were found unconscious from overdoses on consecutive days in June.

'No one should have to go through what I went through, to come home and find their wife dead.'—Sarnia, Ont., man

Fentanyl is a painkiller 100 times more potent than morphine. It is 750 times stronger than codeine, according to Dr. Michelle Arnot, a professor of pharmacology at the University of Toronto.

Det. Const. Ivan Skinn said Fentanyl is “far more dangerous than the old formula of OxyContin.” In 2011, Skinn warned that Fentanyl would replace OxyContin as a problem among addicts before OxyContin was delisted.

Mark Simpson, who requested that his real name not be used to protect the identity of his two children, found his wife dead of a Fentanyl overdose late last year.

Death of 'a perfect wife'

Simpson said she was “a perfect wife” — until she was prescribed Fentanyl.

When she slipped and fell on ice, her injuries required back surgery and left her in pain, so her doctor prescribed Fentanyl patches.

Simpson’s wife soon became addicted. She first sucked the patches under her tongue. Someone then showed her how to smoke them. Simpson said she was eventually burning through a month’s supply of 15, 100-milligram patches in less than a week.

When she could no longer convince her doctor to write a prescription, she forged one.

Simpson learned after his wife’s death that she had a fraud charge against her. As a result of forging her doctor’s name, she could no longer obtain a prescription. So Simpson’s wife turned to the street and bought the drug from dealers.

“Once she figured out how to smoke it, everything went missing. I’ve lost thousands of dollars worth of stuff,” Simpson said. “She would do anything to get drugs. She was selling everything.”

Simpson, 38, said his wife, 34, pawned her children’s laptops and his tools, and took a $10,000 cash advance on his credit card to buy the drugs. He found many of his household items at a local pawn shop.

“It wasn’t my wife,” he said.

Addict led 'secret life'

Simpson routinely worked an afternoon shift, from 3 p.m. to 11 p.m. That’s when his wife abused the painkiller.

“She had a totally secret life,” Simpson said. “It was unbelievable.”

On one of the only days he didn’t come home for lunch during his shift, she died. He found her bleeding, with a straw in mouth, after he came home from work.

“It was the hardest thing to tell my five-year-old,” Simpson said.

Fentanyl patches help deliver the drug throughout the body to people it's given to by prescription. But addicts scrape the drug from the patches and smoke or inject it.

Sarnia police Det. Const. Ivan Skinn warned last year that Fentanyl could become a problem on the streets. (Makda Ghebreslassie/CBC News)

“They take the drug and they go sleep. As they take it, they hope they wake up,” Skinn said. “Every time they take a hit of Fentanyl, they’re playing Russian roulette.”

Skinn said addicts call it “the Fentanyl Nod.”

Police warned of trouble

When the Ontario government delisted OxyContin, Skinn predicted addicts would turn to Fentanyl and heroin.

“It was easy to predict simply because doctors needed to switch their patients to something. People just weren’t going to stop taking OxyContin because the province delisted it,” Skinn said. “The two drugs we’re seeing now [are] Fentanyl and heroin.”

Skinn said patients sometimes sell their patches to addicts or drug dealers for anywhere between $150 and $400 each.

“For us to deal with it on the street is almost impossible because of the existence of a valid prescription somewhere,” Skinn said. “There’s a certain legitimacy about this drug.”

Simpson spoke out because he said the addiction “has to stop.”

“No one should have to go through what I went through, to come home and find their wife dead,” he said.

With files from Makda Ghebreslassie, Greg Layson, Tony Doucette, CBC News