Vomiting Syndrome on the Rise in Heavy Pot Smokers

By R. Scott Rappold

A small but growing number of heavy marijuana users around the world are getting a rare illness that causes vomiting and abdominal pain, and experts are at a loss to explain why.

Cases of cannabinoid hyperemesis syndrome (CHS), also known as cyclical vomiting syndrome, are rare, compared with the overall number of marijuana users, but incidents are on the rise in states that have legal marijuana like Colorado, where what is sold in stores and medical dispensaries is often much stronger than what was long available on the black market.

"When the decriminalization of medical marijuana occurred and the number of medical (marijuana) licenses in the state went up dramatically, we started seeing more and more cases of young, otherwise healthy people who would have multiple recurrent episodes of severe abdominal pain and vomiting and often end up in the emergency room," said Kennon Heard, MD, chief of medical toxicology for the University of Colorado Anschutz Medical Campus in Aurora.

Heard co-authored a study that found such cases doubled at two Colorado hospitals between 2009 and 2011, when the state saw a massive boom in its medical marijuana industry. He does not have updated statistics on cases since Colorado voters legalized recreational marijuana in 2012, but, he said, "If you talk to anyone who practices emergency medicine in the state of Colorado, they're going to tell you they've seen this and they see it fairly frequently, and we see it in our emergency department on a daily or weekly basis."

The problem is not limited to Colorado. Marijuana is now legal for recreational use in eight states and medical use in 28 states, and doctors from Arizona to Oregon to Canada have seen an increase in cases of the syndrome.

It was first discovered in 2004 in Australia, where drug laws are liberal and physicians saw more heavy users of marijuana having bouts of vomiting and abdominal pain that repeated every few weeks or months and lasted for years. All had been daily marijuana smokers for multiple years, according to a study. Quitting made the symptoms go away. And for some reason, the patients found relief from the symptoms with a hot shower or bath.

Only a small percentage of marijuana users had CHS -- the Australian study consisted of just nine patients, and Heard's study identified 36 people with the illness. It appears to remain rare, given that 22 million Americans regularly use marijuana. But quantifying the scope of the problem is difficult.

Heard says it often takes several hospital visits to confirm it, and patients aren't always open about their marijuana use, making it tough to say exactly how many cases occur. He estimates 100 a year.

The Colorado Department of Public Health and Environment also doesn't have a handle on how many cases occur, because it is not yet a diagnosis included in statistical health reports, says Mike Van Dyke, PhD, the agency's chief of toxicology. The department has only just begun to include the illness in its reports on the impacts of legal marijuana and hopes to begin compiling better data.

"It's not hugely prevalent -- thousands upon thousands of patients -- but it's a big enough deal that we're putting out there that this does exist and to stop using has been shown to alleviate the symptoms," says Van Dyke.

It's Not Clear How the Disease Develops

The other major challenge for physicians is that nobody understands how or why marijuana use leads to vomiting or how much marijuana use causes the syndrome. Some people actually use it to combat nausea associated with chemotherapy. Heard suspects long-term use of high-grade marijuana can lead to changes in a system in the body that helps regulate the gastrointestinal tract. Experts say that users who developed the syndrome had been smoking for years. But there has been nothing found to indicate why some users have CHS and others don't.

Experts agree the increased availability of stronger marijuana may be behind the rise in cases.

"People have been smoking pot for a long time, but the widespread availability of very high-potency marijuana is recent," says Eric Lavonas, MD, interim chief of emergency medicine at Denver Health Medical Center. "Prior to legalization, marijuana was something that was grown in a field and smuggled in from wherever it was grown, but marijuana for sale in dispensaries … is much more potent than the marijuana that was around 20 years ago."

IV Fluids and Hot Showers

Doctors can treat the dehydration from vomiting with IV fluids, and the drug haloperidol has shown some success in battling it. Otherwise, they can only tell the patients to stop using marijuana.
And as for the hot shower or bath remedy, that's a big mystery as well.

"I have no idea. Anything that makes my patients feel better, I'm glad, but I don't know why some people react to marijuana in this way. I don't know why a hot shower makes them better. It's going to have to be worked out, but in the meantime, we just want people to stop suffering," says Lavonas.

It used to be common for Lavonas to see maybe one case a year of cyclical vomiting, usually associated with diabetes. Now he sees several a week.

"I'm not for or against marijuana. I am anti-vomiting," he says. "The message I would want people to get is to be informed about anything you do with your body and know this is a possibility."

"If you are a heavy marijuana smoker and you have recurring episodes of severe abdominal pain and vomiting, consider whether this could be you and try stopping for a few weeks and see if it helps."