Treating Cyclic Vomiting and Cannabinoid Hyperemesis: What the Evidence (and Experts) Currently Support

A clinical review maps the landscape of abortive therapies for two poorly understood episodic vomiting disorders, highlighting how little rigorous evidence exists to guide the pharmacologic and nonpharmacologic strategies clinicians commonly use in both home and emergency department settings.

Why This Matters

Cyclic vomiting syndrome and cannabinoid hyperemesis syndrome impose a disproportionate burden on emergency departments, with patients often cycling through repeated visits before receiving a correct diagnosis or a coherent treatment plan. These conditions cause severe functional impairment, and clinicians frequently resort to empiric, experience-based regimens because standardized protocols do not exist. A structured synthesis of current abortive strategies, even one built on limited evidence, meets a genuine clinical need at a time when both conditions appear to be increasing in recognition and prevalence.

Clinical Summary

Cyclic vomiting syndrome (CVS) and cannabinoid hyperemesis syndrome (CHS) are episodic disorders characterized by recurrent, stereotypical bouts of intense nausea and vomiting separated by symptom-free intervals. Both conditions are associated with diagnostic delays, high healthcare utilization, and significant quality-of-life impairment. Published in Neurogastroenterology and Motility in 2025, this narrative clinical review by investigators at the University of Pittsburgh, McMaster University, and the Cyclic Vomiting Syndrome Association synthesizes available literature and expert opinion on abortive therapy, which is the treatment given to halt or shorten an episode once it begins. The mechanistic rationale for early intervention centers on the prodromal phase, a window of approximately 50 minutes before full emesis begins, during which pharmacologic agents such as triptans, ondansetron, or anxiolytics may interrupt the neurohormonal cascade driving the episode.

The review catalogs multiple pharmacologic classes used in practice, including triptans, serotonin receptor antagonists, benzodiazepines, NK-1 receptor antagonists, antipsychotics, and NSAIDs, alongside nonpharmacologic strategies such as sensory reduction, hot water bathing, and topical capsaicin. It provides dosing tables and clinical considerations for each agent. However, the authors are explicit that no randomized controlled trials compare these agents head-to-head, and the evidence supporting any individual therapy is largely observational or based on case series. Key limitations include the absence of a systematic search strategy, the lack of formal evidence grading, and the potential for selective citation inherent to narrative reviews. The authors conclude that more research is needed to develop evidence-based, individualized treatment protocols and to determine whether CVS and CHS require fundamentally different abortive approaches.

Dr. Caplan’s Take

This review does something genuinely useful by organizing the scattered treatment landscape into a coherent reference for clinicians. The prodrome-based treatment framework is the most important clinical insight here: getting the right medication to the right patient before vomiting escalates can mean the difference between a managed episode at home and an ED visit. But I want to be honest with patients and colleagues alike that we are working from clinical pattern recognition and expert opinion, not from the kind of evidence base we would demand for most other conditions. When patients ask me what the “best” treatment is, the truthful answer is that we do not know yet.

In practice, I work with CVS and CHS patients to build individualized abortive regimens, usually starting with a triptan or ondansetron for prodromal use, and I emphasize having a low threshold for early intervention. For patients with frequent ED presentations, I advocate for care plans that are available to treating physicians in the emergency department to reduce inconsistency and avoid the stigmatizing encounters these patients too often describe. I also ensure that any patient with suspected CHS understands that cannabis cessation remains the most evidence-supported intervention for their specific condition.

Clinical Perspective

This review sits squarely in the early stages of the research arc for CVS and CHS abortive therapy. It confirms what most gastroenterologists and emergency physicians already observe in practice: a diverse pharmacologic toolkit is in use, but none of the agents have been rigorously validated against one another or against placebo in well-designed trials. The review’s strength is its practical organization of treatment options by setting (home versus emergency department) and its emphasis on prodromal intervention. Its weakness is that it cannot differentiate between what clinicians do and what actually works, a distinction that matters for patient-facing conversations. Until comparative effectiveness data emerge, clinicians should frame abortive therapy as empirically guided rather than evidence-based.

Several of the agents discussed carry meaningful safety considerations. Benzodiazepines, while effective for the anxiety and insomnia that accompany episodes, carry dependence risk in a population that may experience frequent recurrences. Droperidol and haloperidol require QTc monitoring. Triptans are contraindicated in patients with cardiovascular disease or uncontrolled hypertension. The inclusion of a patient advocacy co-author introduces a perspective that, while valuable, may subtly favor access-oriented framing over strict evidence appraisal. The single most actionable step clinicians can take now is to develop and document individualized abortive care plans for their CVS and CHS patients, ensuring these plans are accessible in the ED and include clear escalation criteria.

Study at a Glance

Study Type

Narrative clinical review with expert opinion

Population

Adults and adolescents with cyclic vomiting syndrome (CVS) and cannabinoid hyperemesis syndrome (CHS)

Intervention

Pharmacologic and nonpharmacologic abortive therapies (triptans, antiemetics, anxiolytics, NK-1 antagonists, antipsychotics, NSAIDs, capsaicin, hot water bathing, sensory reduction)

Comparator

None (no head-to-head or placebo comparisons reviewed)

Primary Outcomes

Episode abortion or shortening; clinical practice patterns

Sample Size

Not applicable (no original data collected)

Journal

Neurogastroenterology and Motility

Year

2025 (accepted August 2024)

DOI

10.1111/nmo.14901

Funding Source

Not reported

What Kind of Evidence Is This

This is a narrative clinical review, which occupies a position near the bottom of the evidence hierarchy, above individual case reports but well below systematic reviews and randomized controlled trials. Narrative reviews do not employ a predefined search strategy, inclusion and exclusion criteria, or formal risk-of-bias assessment, meaning the completeness and representativeness of the cited literature cannot be independently verified. The most important inference constraint this imposes is that readers cannot determine whether the treatment recommendations reflect the full evidence base or a selective reading of it.

How This Fits With the Broader Literature

This review aligns with and extends the North American Society for Neurogastroenterology consensus guidelines on CVS management, which similarly acknowledge the limited evidence base and rely heavily on expert opinion. It is consistent with the 2019 Rome IV working group recommendations regarding early abortive therapy during the prodrome. Where it adds value is in its explicit treatment of CHS alongside CVS, a pairing that remains controversial because some experts consider CHS a distinct entity requiring different management, while others view it as CVS triggered by cannabis. The unresolved question of whether these conditions require different abortive strategies is acknowledged by the authors and represents the most clinically consequential gap in the current literature.

Common Misreadings

The most likely overinterpretation is treating this review as an evidence-based treatment guideline. Readers may see the organized drug tables with dosing information and infer that these represent validated, comparative recommendations. They do not. The review catalogs what clinicians currently use, not what controlled trials have shown to be effective. No agent discussed here has been tested in a rigorous randomized trial specifically for CVS or CHS episode abortion. Similarly, the inclusion of topical capsaicin and hot water bathing as abortive strategies should not be taken as endorsement of their efficacy; the evidence for both remains preliminary and largely anecdotal, particularly outside the CHS subpopulation.

Bottom Line

This narrative review provides a useful clinical reference for organizing the fragmented abortive therapy landscape in CVS and CHS, and its emphasis on prodromal intervention is its most defensible and practical contribution. It does not establish the superiority of any agent or regimen. Clinicians should use it as a starting framework for individualized care planning while remaining transparent with patients that the evidence base remains thin and that treatment selection is currently guided more by clinical experience than by rigorous trial data.

References

1. Bhandari S, Venkatesan T, et al. Abortive therapy for cyclic vomiting syndrome and cannabinoid hyperemesis syndrome. Neurogastroenterology and Motility. 2025. DOI: 10.1111/nmo.14901.
2. Venkatesan T, Levinthal DJ, et al. Role of chronic cannabis use: cyclic vomiting syndrome vs cannabinoid hyperemesis syndrome. Neurogastroenterology and Motility. 2019;31(suppl 2):e13606.
3. Stanghellini V, Chan FKL, et al. Rome IV: gastroduodenal disorders. Gastroenterology. 2016;150(6):1380-1392.
4. Li BUK, Lefevre F, et al. North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition consensus statement on the diagnosis and management of cyclic vomiting syndrome. Journal of Pediatric Gastroenterology and Nutrition. 2008;47(3):379-393.