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Haloperidol vs. Ondansetron for Cannabis Hyperemesis Syndrome

Op-Med is a collection of original articles contributed by Doximity members.

Dr. Joshua Davis is a 2020–2021 Doximity Research Review Fellow. Nothing in this article is intended nor implied to constitute professional medical advice or endorsement. The views expressed in this article are those of the author and do not necessarily reflect the views/position of Doximity. 

A large number of patients experiencing intractable vomiting without an identified cause are high-frequency marijuana users. The legalization of marijuana in many states, and the resulting increase in marijuana use, has led to the recognition and increasing diagnosis of a clinical syndrome called “cannabis hyperemesis syndrome” (CHS). While the treatment for CHS is not well understood, antiemetics seem to be the gold standard. Haloperidol/droperidol, benzodiazepines, and capsaicin have anecdotally proven successful, as well.

In my experience, many patients are “diagnosed” with syndromes such as non-diabetic gastroparesis or cyclic vomiting, but if you dig deeply, they actually meet the criteria for CHS. This is an important part of the history that is often missed. Further, some patients do not consider marijuana a “drug,” so clinicians must ask about it specifically. Many of these patients have not even had confirmatory testing for “gastroparesis” and similar diagnoses. 

The Haloperidol Versus Ondansetron for Cannabis Hyperemesis Syndrome (HaVOC) study enrolled 33 patients, making it the largest randomized study of CHS treatment. Its results showed that haloperidol is more effective than ondansetron for reducing pain, nausea, and length of hospital stay, but suggests that patients receiving higher doses of haloperidol may experience higher rates of dystonia.   

This study confirms my practice of using haloperidol in patients who present with intractable vomiting. I typically shift to haloperidol before ondansetron when I have a high suspicion of  CHS, or if the patient has a history of similar presentations. I typically use 2.5–5 milligrams (which equals the lower haloperidol dose in this study) with good success and very low rates of dystonia and other adverse effects.

In future research, I’d be interested in a comparative study of haloperidol and droperidol, which is back on the market after a hiatus due to largely overblown QT prolongation concerns. Droperidol is not yet available to me, but I’d be interested in whether it outperforms haloperidol in CHS patients. In the meantime, I am heartened to have my clinical practice confirmed by formal research. Now, if only we could find a way to convince these patients that the marijuana is what is causing the vomiting … and get them to quit….

Dr. Joshua Davis is an emergency physician who completed his residency at Penn State Milton S. Hershey Medical Center. He completed medical school at Thomas Jefferson University and received his undergraduate degree from the University of Delaware. His research interests are broad and include emergency medicine topics along with patient safety, handoff communication, and diet and exercise.

Image: Leka Sergeeva / shutterstock

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