Top Calgary ER doctor sees spike in cannabis 'poisoning'

Calgary's top emergency room doctor says he's seeing an increase in illnesses dubbed "cannabis poisoning."

He expects to see more such cases once the drug is legalized in Canada, at least initially.

"I'm very concerned. Our experience with colleagues down in Colorado is that especially in the first six to 12 months after legalization, the number of cannabis-related emergency department visits increased significantly," Lang told the Calgary Eyeopener on Monday.

"However, we are also hearing that after that initial trial period ... that tends to die off."

'Paradoxical thing'

Lang said that while he hasn't collected statistics, he and other doctors have seen an increasing number of cannabis users coming in.

Some are suffering from psychological issues, such as paranoia, disturbed thinking or a triggered mental illness, or an illness called cannabis hyperemesis syndrome.

"That's cannabis extra vomiting syndrome, if you will, and this is usually in the regular users who are coming in with an uncontrollable, one- to two-day attack of vomiting where it will be unstoppable, several times an hour," Lang said.

"It's just kind of a paradoxical thing because marijuana usually controls nausea but in some people, it has this opposite effect."

The various issues are generically called "cannabis poisoning" but that's not to equate the symptoms with alcohol poisoning, which can be deadly and is much more common.

However, the cannabis-related illnesses are becoming increasingly common as new people try out cannabis, he said, and then go to the emergency when suffering strange effects.

Many chronic pain patients also are trying cannabis for the first time, as physicians and patients are more cautious about addictive opioids. These patients are more often suffering the vomiting symptoms, Lang said, whereas young patients, ages 15 to 25, are more likely to suffer psychological issues.


To treat cannabis hyperemesis syndrome, emergency medical teams may keep the patient under observation for up to 36 hours, provide intravenous liquids, anti-nausea medication.

They also sometimes spread hot pepper cream on their torsos to replicate the heat patients seek to relieve the symptoms, Lang said. Often he sees patients who've tried to self-treat their vomiting through taking hot showers or baths.

'More challenging'

The psychological cases "are a bit more challenging to deal with," he said. The medical team tries to glean medical history and recent events from the patient and their family.

"Sometimes we just have to admit them to the hospital and, hopefully, as the cannabis wears off, the disturbed thinking and the paranoia fades away and we encourage them not to use it again," Lang said.

Sometimes it's a matter of the effects of cannabis revealing a developing mental illness, he said. Other times, the patient is using cannabis to treat an underlying mental illness, such as anxiety, and then when they don't take it, they may end up in a crisis.

Treatment can require hospitalizing the patient for up to 72 hours, which is a great draw on resources, Lang said.

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​With files from the Calgary Eyeopener.