What Works and What Doesn’t When CVS and CHS Attacks Strike at Home or in the ER

A clinical review maps out abortive treatment options for two poorly understood vomiting disorders, synthesizing pharmacologic and non-pharmacologic strategies across home and emergency department settings while candidly acknowledging that the limited evidence base underlying most recommendations consists largely of case series and expert consensus rather than randomized trials.

Why This Matters

Cyclic vomiting syndrome and cannabinoid hyperemesis syndrome impose severe episodic burdens that drive patients to emergency departments repeatedly, often encountering inconsistent care and clinical skepticism. Both conditions remain underdiagnosed and undertreated, with acute episodes carrying real risks including dehydration, electrolyte disturbances, and Mallory-Weiss tears. Despite growing recognition, no comprehensive evidence-based guideline has existed for aborting acute episodes. A 2025 review that organizes scattered clinical knowledge into a practical framework arrives at a moment when clinicians urgently need structured guidance, even as the field awaits the randomized trial data that would make that guidance definitive.

Clinical Summary

Cyclic vomiting syndrome and cannabinoid hyperemesis syndrome share a clinical phenotype of recurrent, stereotypical episodes of intense nausea and vomiting, but their underlying pathophysiology and triggers differ. A narrative clinical review published in Neurogastroenterology and Motility in 2025 by Venkatesan, Gala, and colleagues consolidates available pharmacologic and non-pharmacologic approaches to aborting these episodes, organized by treatment setting. The mechanistic rationale spans several pathways: triptans target the serotonergic signaling implicated in CVS migraine-variant pathophysiology, NK-1 receptor antagonists block substance P-mediated emesis, benzodiazepines address the autonomic hyperactivation common during prodromal phases, and topical capsaicin exploits TRPV1 receptor desensitization relevant to CHS. The authors emphasize that the prodromal window, estimated at a median of approximately 50 minutes before emesis onset, represents the critical opportunity for intervention.

The review describes multiple drug classes available for abortive use, including ondansetron, promethazine, prochlorperazine, haloperidol, droperidol, alprazolam, lorazepam, aprepitant, fosaprepitant, diphenhydramine, and NSAIDs, alongside non-pharmacologic strategies such as sensory reduction, hot water bathing, and topical capsaicin cream. However, no head-to-head comparative trial data exist to distinguish which agents are superior for specific patient populations or episode subtypes. Topical capsaicin evidence comes primarily from small case series in emergency department settings for CHS. The authors acknowledge that their recommendations rest on case-level evidence and expert inference, not randomized controlled trials, and they explicitly state that more research is needed to develop evidence-based, individualized abortive treatment plans and to determine whether CVS and CHS require fundamentally different therapeutic approaches.

Dr. Caplan’s Take

This review does something genuinely valuable by organizing a fragmented treatment landscape into a usable clinical reference. The medication table alone gives practitioners a starting framework they often lack. But the honest core of this paper is its acknowledgment that we are treating based on pattern recognition and pathophysiologic reasoning rather than comparative trial data. Patients with CVS and CHS regularly ask me what will stop their episodes, and a responsible answer requires explaining that we have several plausible options but limited ability to predict which will work for them specifically.

In practice, I work with patients to identify their prodromal signals and build a tiered home protocol, usually beginning with ondansetron and a benzodiazepine, with clear escalation criteria for emergency department presentation. For patients who cycle through the ED frequently, I strongly advocate co-developing a written care plan they can carry with them. This reduces the variability in emergency treatment that so many of these patients experience and helps ensure they receive consistent, effective, and compassionate care.

Clinical Perspective

This review sits at an early point in the research arc for both CVS and CHS abortive therapy. It consolidates what is known but cannot advance the evidence base because it presents no original data and employs no systematic methodology. For clinicians, the practical takeaway is that the prodromal phase represents the most actionable treatment window, and multimodal regimens tailored to individual patients remain the standard of care by necessity rather than by proof of superiority. The evidence does not currently support recommending any single agent as first-line with high confidence, and it does not yet distinguish whether CVS and CHS respond to fundamentally different pharmacologic strategies. Patient-facing recommendations should be framed as individualized trials rather than definitive prescriptions.

Several pharmacologic considerations deserve attention. Benzodiazepines carry dependence risk with repeated use across frequent episodes. Haloperidol and droperidol require QTc monitoring, particularly in patients who may be volume-depleted and hypokalemic during episodes. Triptans are contraindicated in patients with cardiovascular disease or uncontrolled hypertension. Topical capsaicin, while low-risk, has evidence limited to CHS in emergency department settings and should not be generalized to CVS without further study. The single most actionable recommendation clinicians can implement now is to initiate the development of a written, individualized emergency department care plan for any patient presenting with recurrent CVS or CHS episodes, ensuring continuity of treatment across providers and visits.

Study at a Glance

Study Type

Narrative clinical review

Population

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

Intervention

Pharmacologic (triptans, antiemetics, anxiolytics, NK-1 antagonists, antipsychotics, NSAIDs) and non-pharmacologic (sensory reduction, hot water bathing, topical capsaicin) abortive strategies

Comparator

None; no head-to-head comparisons reviewed

Primary Outcomes

Episode abortion and symptom reduction in home and emergency department settings

Sample Size

Not applicable; no original data collected

Journal

Neurogastroenterology & Motility

Year

2025 (accepted August 2024)

DOI

10.1111/nmo.14901

Funding Source

Not reported; one author affiliated with a CVS patient advocacy organization

What Kind of Evidence Is This

This is a narrative clinical review, which sits below systematic reviews and meta-analyses in the evidence hierarchy and well below randomized controlled trials. It synthesizes existing literature and expert opinion without a reported formal search strategy, inclusion or exclusion criteria, or risk-of-bias assessment. The single most important inference constraint this design imposes is that the selection of cited evidence may reflect the authors’ clinical perspectives and priorities rather than the totality of available data, meaning that both the completeness and the balance of the recommendations cannot be independently verified from the review alone.

How This Fits With the Broader Literature

This review is broadly consistent with prior consensus guidance, including the 2019 Rome IV-based recommendations for CVS management and the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition (NASPGHAN) consensus statement, both of which highlighted the limited evidence base and the reliance on expert opinion for treatment decisions. It extends the conversation by explicitly addressing CHS alongside CVS and by incorporating the emerging interest in topical capsaicin, which has been described in small case series such as the work by Dezieck and colleagues in 2017. Notably, no major new trial data have appeared since prior consensus documents to substantially shift the evidence landscape, meaning this review consolidates rather than transforms the field.

Common Misreadings

The most likely overinterpretation of this review is treating its medication recommendations as an evidence-based treatment algorithm with established hierarchies of efficacy. The review explicitly lacks comparative data. It cannot tell clinicians which drug is best for which patient, and it does not provide effect sizes, number-needed-to-treat figures, or response rates. Similarly, the inclusion of topical capsaicin should not be read as endorsement of its efficacy for CVS; the available evidence pertains almost exclusively to CHS in emergency department settings. Finally, the affiliation of one author with a patient advocacy organization is worth noting, not as a disqualification but as context for possible framing priorities favoring treatment access and patient experience.

Bottom Line

This narrative review provides a useful clinical reference for managing acute CVS and CHS episodes, consolidating scattered recommendations into a practical framework organized by treatment setting. It does not establish comparative efficacy for any intervention, and all recommendations rest on case-level evidence and expert opinion. For practice now, the review reinforces that early prodromal intervention and individualized emergency department care plans represent the most defensible strategies while the field awaits the randomized trial data it urgently needs.

References

1. Venkatesan T, Gala K, et al. Abortive therapy for cyclic vomiting syndrome and cannabinoid hyperemesis syndrome: home and emergency department management. Neurogastroenterology & Motility. 2025. DOI: 10.1111/nmo.14901.
2. Dezieck L, Hafez Z, Conicella A, et al. Resolution of cannabis hyperemesis syndrome with topical capsaicin in the emergency department: a case series. Clinical Toxicology. 2017;55(8):908-913.