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Here you will find articles and research on Cannabinoid Hyperemesis Syndrome and it's treatment.
We will regularly update this page, so check back often to stay in the loop.
Cannabinoid hyperemesis syndrome (CHS): A syndrome characterized by episodic nausea and vomiting among frequent cannabis users that is often relieved by hot bathing.
Disclaimer: We are ER doctors, not researchers. We don’t understand all the complexities of cannabinoid hyperemesis syndrome (CHS), but we have successfully treated hundreds of CHS patients with topical capsaicin (and unsuccessfully with a lot of other medications). We know CHS is real and that capsaicin works. Below is an overview of CHS to the best of our current knowledge. The supporting articles and studies follow, and are frequently updated as more information becomes available.
The conundrum of CHS
There are things I believe but don’t fully understand, like gravity. I don’t really understand it, but I accept that it’s real since I’ve always known it to exist. Every time I fall off my skateboard, I hit the ground. When my three-year-old falls, it’s always down, never up. Making sense of the world in this usual way makes it difficult to understand CHS. How can it be that marijuana alleviates nausea for years, and then starts making you puke? What would my son think if, after years of falling down, he started falling up? It’s hard to accept that something you’ve always known to be true could sometimes be the opposite.
It’s difficult to imagine that marijuana can cause vomiting, or that CHS is a real syndrome. THC alleviates nausea; it’s prescribed for nausea. Confusing things even more are the facts that CHS only affects people who have used marijuana for a long time, and some people use marijuana for years and never get CHS. No wonder there are CHS non-believers. And I wouldn’t mind, except that when people get CHS, they are absolutely miserable. They often end up in the ER, and it’s really hard to get them feeling better with any available medications or treatments. Many patients with CHS have recurrent hospital admissions for dehydration, inability to tolerate oral intake, and even renal failure.
CHS is not as well studied or understood as other medical conditions since it’s relatively newly described and pharmaceutical companies haven’t published studies aimed at selling expensive treatments for it (yet). Currently, the only medications that seem to help people with CHS are injectable antipsychotics and topical capsaicin (the compound that makes hot peppers hot).
First described in 2004, CHS is characterized by frequent cannabis use, recurrent episodes of intractable nausea and vomiting, and improvement with hot bathing. While underreported, it’s thought to affect 2.75 million people in the U.S., and the incidence is growing with marijuana legalization. CHS can be divided into three phases: prodromal, hyperemetic, and recovery. The prodromal phase lasts for months to years, with people developing morning nausea, fear of vomiting, and abdominal pain. During this phase, people often continue or even increase their cannabis use in an attempt to alleviate their symptoms. The hyperemetic phase is characterized by episodes of abdominal pain, and intense, incapacitating nausea and vomiting. During the recovery phase symptoms resolve for days to months before the cycle starts again.
Tetrahydrocannabinol (THC), cannabidiol (CBD), and cannabigerol (CBG) are cannabinoids with differing effects on the emesis (vomiting) response. THC has approximately100 known breakdown products with differing psychotropic, anti-inflammatory, analgesic, and other effects. CBD modulates the anti-emetic effects of THC. In animal studies, low dose CBD inhibits vomiting, while high dose CBD promotes vomiting. CBG appears to oppose the anti-emetic effect of low dose CBD, directly promote vomiting, and play an important role in CHS.
Why does CHS only occur with long-term marijuana use?
Based on the available evidence, here is my (simplified) understanding of it: CHS is likely due in part to desensitization of the TRPV1 receptor (see below), and the solubility of cannabinoids. Cannabinoids are very fat-soluble. Storage in fat causes them to remain in the body for a long time (this explains why people can have a positive drug screen long after their last marijuana use). One theory is that the pro-emetic cannabinoids may be stored in the body longer and at higher concentrations than the anti-emetic cannabinoids. However, while their storage is greater, pro-emetic cannabinoids are present at lower concentrations in marijuana than are anti-emetic cannabinoids. Thus, it may take years of marijuana use to accumulate high enough concentrations of these compounds (and desensitization of the TRPV1 receptor) for them to have a significant pro-emetic effect.
Why do people only get sick intermittently?
During times of fasting (e.g. overnight) or times of stress, the body undergoes increased lipolysis (fat breakdown) for fuel. Fat breakdown results in release of both the pro and anti-emetic cannabinoids, and the relative proportions of these cannabinoids influences the net effect that they have on vomiting. This explains the prodromal phase of CHS where people initially develop morning nausea- fat breakdown overnight releases low levels of pro-emetic cannabinoids, but once a person ingests food and lipolysis is inhibited, symptoms resolve.
However, as higher concentrations of pro-emetic cannabinoids accumulate, lipolysis results in release of large amounts of these compounds, and vomiting begins. The stress of vomiting results in increased lipolysis, which results in increased release of pro-emetic compounds, and a positive feedback loop is created. More vomiting results in more release of more pro-emetic cannabinoids into the blood, and more stimulus to vomit. Thus, the intractable vomiting of CHS… More puking causes more stimulus to puke, and things spiral out of control.
What treatments are available/effective for treating CHS?
The only thing that “cures” CHS is cessation of marijuana use. However, almost all people feel better with hot bathing, and topical capsaicin (hence Dr. Z’s Weed Cream). Injectable dopaminergic antipsychotic medications (e.g. Haldol and Zyprexa) also seem to have some benefit (but who wants injections of antipsychotics with all their side effects when topical capsaicin works as well or better?).
Why do hot bathing and capsaicin work for CHS?
Patients usually figure out on their own that their symptoms improve in very hot baths or showers (one of the hallmarks of CHS). While initially CHS was solely attributed to stimulation of CB1 (cannabinoid receptor type I), this failed to explain why only some people develop CHS, the latency from onset of marijuana use to symptoms, and why only chronic users are affected. It additionally doesn’t explain why capsaicin and hot water are effective at alleviating symptoms.
It is now thought that a receptor named TRPV1 (transient receptor potential vanilloid subtype 1), which is found in the GI tract, various neurons, and central nervous system (CNS), is largely responsible for CHS.
The TRPV1 receptor, which is stimulated by cannabinoids, heat, and capsaicin, has potent anti-emetic effects. Prolonged exposure to cannabinoids may result in down-regulation/inactivation of the TRPV1 receptor. Hot-water bathing may normalize diminished TRPV1 activity by exposure to another TRPV1 stimulus. Topical capsaicin, which has a longer half-life than oral capsaicin, also augments TRPV1 activity and provides dramatic relief of symptoms, likely by the same mechanism as hot water exposure.
There is still a lot to learn about CHS, it’s causes, and ways to treat it. We’re fortunate that somebody smarter than us figured out that topical capsaicin is effective in treating CHS. While only complete cessation of marijuana use truly cures CHS, for those who want to continue to enjoy marijuana, topical capsaicin is effective for alleviating their symptoms (as proven by numerous studies and hundreds of our patients). Dr. Z’s Weed Cream smells and feels great, and is the only safe, effective over the counter treatment available for CHS.
We’re here to help,