Does Marijuana Prevent Nausea and Vomiting…or Cause It?

Last updated on November 4th, 2019

Most people think marijuana prevents nausea and vomiting, but can it have just the opposite effect in some circumstances?

Common among the approved uses in the 25 states that, as of mid 2016, allow limited access to marijuana or its active components – delta-9-tetrahydrocannabinol (THC) and cannabidiol – for medical reasons is severe nausea, and such problems as glaucoma, cancer, HIV/AIDS, chronic pain, and seizures. But few people know – nor do medical professionals – that in a select group of individuals, THC can have a paradoxical effect, acting as an antiemetic (preventing nausea) at one level but causing nausea and vomiting at higher levels when used over prolonged periods. (Cannabis sativa is the scientific name for the marijuana plant – “cannabis” and “marijuana” are often used interchangeably.)

…few people know – nor do medical professionals – that in a select group of individuals, THC can have a paradoxical effect, acting as an antiemetic (preventing nausea) at one level but causing nausea and vomiting at higher levels when used over prolonged periods.-Anne FletcherPicture someone close to you with prolonged daily nausea and vomiting who winds up having countless medical tests with diagnoses ranging from food poisoning to Crohn’s disease to irritable bowel syndrome. Between all the tests and many prescribed medications, costs climb into the $50-60,000 range. But he gets no better. Such was the case of the brother of Thomas Lee, a Master of Health Administration student at Florida Atlantic University College of Business as shared in a YouTube continuing education lecture for physicians. Lee noted, too, that his brother would sit in the shower for four to five hours a day, until the hot water heater “blew out,” which then led to a diagnosis of obsessive compulsive disorder. Finally, Lee’s own Google search of the terms “showering and vomiting” (try it) led to “cannabinoid hyperemesis syndrome” (CHS.) In fact, every entry on the first page of the search led to this condition involving cyclic vomiting associated with compulsive bathing and chronic marijuana smoking.

Lee said, “We never thought anything about marijuana smoking because it’s so associated with promoting appetite and preventing nausea.” This information was then presented to the brother’s physician, who still couldn’t explain what was wrong. In turn, Lee began to wonder why doctors are so misinformed about marijuana ­– in particular about this paradoxical condition. (He soon found The Answer Page, a website developed by a Harvard Medical School professor that provides continuing education to physicians, including education on medical marijuana use. Lee described this resource as unbiased and not motivated by political or financial interest, honestly presenting “the positive and negative aspects of cannabis so physicians can advise the most effective treatment plan.”)

How Common is CHS? 

In his presentation on CHS Lee said, “It’s very rare; it’s not seen very often.” Certainly, one can find multiple case reports in the scientific literature, typically of people who, like Lee’s brother, go through extensive medical testing before it’s discovered that CHS is the source of their problems. One case reported early this year in Clinical Neuropharmacology was titled, “An Overlooked Victim of Cannabis: Losing Several Years of Well-being and Inches of Jejunum on the Way to Unravel Her Hyperemesis Enigma.”  (The jejunum is part of the small intestine.) After an “odyssey of hospital stays” the patient found via the Internet that she had CHS, and her symptoms went away after abstaining from cannabis.

Finding experts on this topic isn’t an easy task but after networking I located Ethan Russo, MD, a neurologist and internationally recognized expert in cannabis pharmacology and its medical use. As past president of the Cannabinoid Research Society and past chairman and current board member of the International Association for Cannabinoid Medicines, Russo is current medical director of PHYTECS, a company developing products that help individuals maintain proper function of the endocannabinoid system, a unique communication system in the brain and body. Russo told me, “CHS is rare, so it’s hard to study. And we don’t have the tools to study it. Something over 100 cases are reported in the world literature. That’s not impressive, but that’s not to say it’s not serious.”

Endocannabanoids are natural chemicals made by the body influencing many physiological systems including appetite, pain, muscle control, metabolism, sleep health, stress responses, motivation, mood, and memory. Cannabinoid receptors – divided into two main subtypes, CB1 and CB2 – are important cell membrane receptors in many parts of the body that affect cells and determine the effects of natural endocannabanoids as well as THC taken as a drug. (CB1 appears to have more to do with nausea and vomiting that does CB2.)

Psychiatrist Kevin Hill, MD, MHS of McLean Hospital and Harvard Medical School and author of Marijuana: The Unbiased Truth About the World’s Most Popular Weed consults on an inpatient psychiatric unit where he said, “I usually encounter patients with CHS about once a month. But we don’t know how common it is in part due to lack of reporting. Anecdotally, it appears that cases of CHS are on the rise as potency of marijuana increases and use of concentrates becomes more common.  Most of the cases we have seen lately on my service have involved concentrates.” (A marijuana concentrate is a highly potent THC-concentrated mass that looks like honey or butter. Concentrates can be used orally in foods or drink products, smoked in water or oil pipes, or used in e-cigarettes or vaporizers.)

What Causes CHS?

Russo made it clear that we don’t know specifically what causes CHS and that he doesn’t agree with most theories presented in scientific reviews of the syndrome. He said, “It’s all still theories. It’s clear that it only occurs in chronic high-dose THC use, mainly in people who don’t want to quit. It is usually in someone with chronic heavy consumption – dependency. It could pertain to a down-regulation of CB1 receptors in the areas of the brain that have to do with nausea. You’ve got this person who’s smoking a great deal who develops intractable vomiting. They figure out that the only thing that helps is hot showers or baths and it freaks out the people around them – the hot showers or baths are fairly indicative of CHS. There is always the possibility that someone does not notice the association. Otherwise, it is a diagnosis of exclusion.”

…CHS patients frequently undergo extensive gastrointestinal work-ups without positive findings, and then CHS diagnosis is unlikely unless the clinician asks the right questions about cannabis use and knows of the syndrome’s existence.-Anne FletcherLike Lee’s brother and the case described above, CHS patients frequently undergo extensive gastrointestinal work-ups without positive findings, and then CHS diagnosis is unlikely unless the clinician asks the right questions about cannabis use and knows of the syndrome’s existence. Hill said, “This underscores the importance of the doctor-patient relationship.  Chronic nausea and vomiting should be addressed by a doctor that knows the patient well, as opposed to a doctor that sees a patient once or twice a year.”

However, Russo maintains that people with CHS are often referred to gastroenterologists who are unfamiliar with cannabis biochemistry. “None of this is taught in medical school,” he added. He also pointed out that it’s not known why CHS only occurs in some people. “They may have a gene mutation in whatever regulates the endocannabanoid system.”

Can CHS be Over Diagnosed?

I recently encountered someone who, for months, had had daily nausea and vomiting accompanied by abdominal and epigastric (above the abdomen) pain. After several years of heavy drinking that resulted in recurrent bouts of acute pancreatitis – an extremely painful condition – he had been abstinent from alcohol for nine months. To relieve the nausea and vomiting, he smoked marijuana regularly.

Like Lee’s brother, my acquaintance went to multiple physicians, was diagnosed with myriad conditions including a stomach virus and later on a possible ulcer, which didn’t respond to medications. Following a CAT scan and blood tests, he was told that everything was fine with the exception of having constipation. The nausea and vomiting continued for months and didn’t respond to the strongest prescription anti-nausea medications. Finally, he went to one of this country’s most prominent medical facilities, was diagnosed with chronic pancreatitis, a very serious condition for which there is little medical relief, and told to stop using marijuana because CHS was likely. This was the first time I had heard of CHS, and none of the substance use disorder colleagues with whom I work had ever heard of it.

This time, what appeared to be the clinic’s blanket recommendation to have patients stop marijuana use because of the likelihood of CHS was off the mark. No assessment was performed to determine how much marijuana the patient was using, nor was he asked about hot shower or bath taking. (No abnormal behavior was going on.) An article about CHS was shared with his personal physician (an addiction specialist) who, like most doctors, was unfamiliar the condition. After doing as assessment, this doctor ruled CHS out and referred the man to a medical marijuana dispensary to get the proper products to help alleviate his condition.

When I asked Hill, if it makes sense for a medical practice to take all cannabis-using patients who present with chronic nausea and vomiting off cannabis because of the possibility of CHS he said, “It’s important to look at each case individually in order to make an appropriate diagnosis.  Cannabis often ameliorates nausea, so uniformly stopping cannabis may not be the best move clinically.”

Hill pointed out, “It’s a challenge to know when cannabis may be helping the patient or harming the patient. Russo talked about the “biphasic effect” of marijuana – that is, it has one effect at a lower dose and another effect at a high dose. For someone who has a chronic pain condition, Russo advises using use a dose that gives pain relief but that doesn’t get them high. “You need to find that sweet spot,” he said. “This is harder if the form of marijuana is inhaled.”

Treating a severe marijuana use disorder (dependence or addiction) to help someone stop using cannabis is another thing altogether. Both physicians agreed that it’s not easy. Russo said, “People with CHS tend to relapse after quitting, but they may be able to use moderately down the road.” Hill stressed the need for a combination of cognitive behavioral therapy and treatment of co-occurring mental health disorders.

Image Courtesy of iStock

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