Deadly effects of fentanyl almost impossible for users to detect: Toxicologist

At the beginning of the second week of the trial of a Yellowknife man who admitted to trafficking a type of fentanyl, a toxicologist says as little as a few thousandths of a gram of the drug can be lethal.

Graham Jones, a former chief toxicologist with the Office of the Chief Medical Examiner of Alberta, testified Monday in the trial of Darcy Oake. The 24-year-old has been charged with criminal negligence causing bodily harm for supplying furanyl fentanyl to a woman who subsequently overdosed. The woman recovered and testified earlier in the trial.

At the start of his trial, Oake pleaded guilty to trafficking furanyl fentanyl. He is facing two other drug charges that he pleaded not guilty to. Oake was charged almost three years ago.

In court, Jones said it is difficult to compare the potency of furanyl fentanyl to fentanyl because no clinical trials have been done on furanyl fentanyl. He said it was created by those hoping to capitalize on the illegal fentanyl market; the drug has similar effects to fentanyl but has enough chemical differences to be considered a new, legal drug.

Jones said users have reported different potency levels of furanyl fentanyl, from one fifth the strength of fentanyl to the equivalent of it. Fentanyl is far more potent than other painkillers — 50 to 100 times the strength of morphine and 25 to 50 times more powerful than heroin.

Fentanyl can be lethal because it can block the receptors in the brain that sense the buildup of carbon dioxide in the blood, Jones explained. Breathing then drops below the rate required to keep up oxygen levels in the blood.

Jones said the deadly effect is almost impossible for users to detect. 

"Once you're starting to experience respiratory depression, you're probably already unconscious or close to it."

Wide variation in tolerance to drug

Despite the strength of the drugs, people can build up incredible tolerance to fentanyl and furanyl fentanyl through regular use, said Jones. He cited the case of a woman who wore 35 fentanyl patches at one time and did not appear intoxicated. In another, a man consumed 20 to 25 pills a day for pain treatment. Jones said one of those pills was enough to kill a person who has not taken the drug.

The woman who overdosed in relation to Oake's case testified she had been addicted to fentanyl, taking it once a day for about a year. She said she blacked out moments after snorting a line Oake had prepared for her. She said the line was "way bigger" than usual. According to the prosecutor, tests done on the furanyl fentanyl seized from Oake found it to be 59 per cent pure.

Oake's lawyer, Peter Harte, asked Jones what effect a person would experience if they snorted one gram of 59 per cent pure furanyl fentanyl. Jones said would be "an incredibly high dose... the equivalent of 100 times what some people regard as a lethal dose in a non-tolerant person."

The woman said she did not regain consciousness until more than a day later, when she woke up on her couch and had to crawl to the washroom.

Harte suggested the woman was suffering the effects of a combination of the tranquillizers she bought and the furanyl fentanyl she got from Oake, a combination Jones said can be extremely dangerous because of the way the drugs act on different receptors in the brain.

But the woman testified she took no other drugs or alcohol before or after taking Oake's furanyl fentanyl. She said she suffered numbness and pain that continued for six months after taking the drug.

Oake's trial is scheduled to continue this week.