Four patients with cannabinoid hyperemesis syndrome that did not respond to standard treatments all improved after receiving olanzapine, an atypical antipsychotic.
Emergency medicine physicians, gastroenterologists, and clinicians managing CHS.
4 of 4 treatment-refractory CHS cases remitted with olanzapine
What the researchers found
All four cases of treatment-refractory CHS remitted after olanzapine treatment. Olanzapine blocks multiple neurotransmitter receptors involved in nausea and vomiting. The authors suggest it may be particularly useful when CHS presents alongside psychotic symptoms or agitation.
Why it matters
CHS is increasingly recognized as cannabis use grows, and some cases do not respond to standard anti-emetics or hot showers. Having additional treatment options for refractory cases addresses a real clinical gap.
The numbers in context
4 patients. All had treatment-refractory CHS. All remitted with olanzapine. Olanzapine targets dopamine, serotonin, histamine, and muscarinic receptors involved in emesis.
How the study worked
Case series of 4 patients with treatment-refractory cannabinoid hyperemesis syndrome treated with olanzapine at a single institution. Clinical outcomes documented before and after olanzapine initiation.
What this study cannot tell us
Only 4 cases with no control group. Cannot rule out spontaneous resolution. No standardized dosing protocol reported. Single institution.
How to read the evidence
Very small case series with no controls. Preliminary signal only.
When this study was published
2021 case series.
The bigger picture
Cannabis cessation remains the definitive treatment for CHS, but patients often cannot or will not stop immediately. Olanzapine could serve as a bridge treatment for acute refractory episodes, borrowing from its established role in chemotherapy-induced nausea.
Questions still open
- What is the optimal olanzapine dose for CHS? Would it work as first-line treatment? Does it address the underlying pathophysiology or just mask symptoms? How does it compare to haloperidol, which has also been tried for CHS?
Common questions
What is cannabinoid hyperemesis syndrome?
Why might olanzapine work for CHS?
Read the original research
Treatment of Cannabinoid Hyperemesis With Olanzapine: A Case Series.
Journal of psychiatric practice, 27(4), 316-321
Citation
Hsu, Jennifer; Herrmann, Zachary; Kashyap, Saurabh; Claassen, Cynthia. (2021). Treatment of Cannabinoid Hyperemesis With Olanzapine: A Case Series.. Journal of psychiatric practice, 27(4), 316-321. https://doi.org/10.1097/PRA.0000000000000564
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