06/01/2013 01:29 EDT | Updated 07/31/2013 05:12 EDT

Spike in fatal fentanyl overdoses sparks warning in B.C.

Health officials in B.C. have issued a warning to drug users to stay away from a powerful prescription painkiller that has been linked to nearly two-dozen deaths in the province already this year.

Fentanyl patches are normally prescribed to treat chronic pain for cancer patients and others, but it's also increasingly being sold illegally to heroin addicts trying to get a fix.

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Pharmacy manager Anil Kanji says the drug is normally dispensed as skin patches designed to disburse the extremely potent drug through the body over two to three days.

"It's 100 times potent than morphine is, so it's a very potent medication for pain relief and potentially abuse."

That abuse prompted Provincial Health Officer Dr. Perry Kendall to issue a warning about a sudden spike in fatal fentanyl overdoses, this week.

Kendall says the B.C. Coroners Service has recorded 23 deaths associated with fentanyl in the first four months of this year.

In comparison in 2012 there were 20 deaths for the entire year, and in 2011 only eight.

A large supply of the drug was seized by Vancouver police recently in connection with two overdose events and across Canada fentanyl on the streets is causing alarm.

Just this month in Montreal police issued a warning after seizing thousands of pills of the drug. During a 2006 fentanyl epidemic in Chicago, 342 people died.

Johnny Gulbrandsen says he has used heroin for the past 30 years. On Friday, as part of his volunteer work for the Insite supervised injection facility, he was warning others of the deadly drug by putting up posters around Vancouver's Downtown Eastside.

"It's very scary. I'm always leery about what I buy... so I'm really worried about that stuff," said Gulbrandsen.