Drug users who test their drugs and discover fentanyl are 10 times more likely to reduce their dose, raising the possibility that making such tests widely available could reduce overdoses.
That is one finding of a drug-checking pilot project at Insite, Vancouver's supervised-injection site, operated by Vancouver Coastal Health (VCH). Launched last July, the initiative offers drug users the option of testing their drugs for fentanyl using a simple test strip, which produces results in seconds.
From July to March, Insite clients checked their drugs more than 1,000 times. In all, 79 per cent tested positive for fentanyl, including 83 per cent of drugs reported to be heroin, 82 per cent crystal meth and 40 per cent cocaine.
Of those who tested their drugs before using them, the ones who discovered the presence of fentanyl were 10 times more likely to reduce their doses – and 25-per-cent less likely to overdose.
"It shows that this is a potential way to reduce harm," said Mark Lysyshyn, medical health officer for Vancouver Coastal Health.
To use the tests, which are adapted from urine tests, users mix a few grains of their drugs with water in a cooker and then submerge a test strip into the solution. A result appears within seconds: One line means it contains fentanyl; two lines mean it does not.
But the tests have their limitations. For one, they only test for fentanyl – not any of its numerous analogues, some of which have been confirmed to be in B.C. And, they don't test for the quantity of fentanyl present.
Dr. Lysyshyn said the health authority is now having discussions with partners about how best to expand the initiative, but cautions there is still much research to be done and "this is only the very beginning of drug-checking."
The manufacturers of the test strips are also working on new strips that can also detect fentanyl analogues, Dr. Lysyshyn said. It's not yet known when those might be available.
Fentanyl has been detected in a growing percentage of illicit-drug overdose deaths since 2012, the first year the BC Coroners Service began testing for it and keeping detailed data. The synthetic opioid was found in around 5 per cent of overdose deaths in 2012, compared with more than 60 per cent now.
More recently, several stronger analogues have been detected in B.C. Carfentanil, for example, is suspected to be the cause of a surge in overdose deaths from November through January. Overdoses on these more powerful opioids can require up to eight doses of naloxone to revive a person, compared with one or two doses for a heroin overdose.
Provincial Health Officer Perry Kendall noted there exist dozens of types of fentanyl and it's expected that more will arrive in B.C. He had called for the decriminalization and regulation of drugs, noting only so much can be done to respond to a toxic drug supply.
"Trying to chase one analogue after another in real time is not a real fruitful exercise," Dr. Kendall said. "There are dozens of fentanyls and we have no ability to test for [them all]. And even if we did, I don't know if it would change our reaction to it."
About 90 per cent of overdose deaths happen indoors. Patricia Daly, chief medical health officer for VCH, said for those who insist on using alone, such drug tests have the potential to save lives.