Comprehensive review of cannabinoid hyperemesis syndrome: three phases, paradoxical vomiting from an antiemetic drug | Research

The takeaway

A review characterized CHS as a three-phase condition (prodromal, hyperemetic, recovery) where cannabis paradoxically causes vomiting despite its established anti-emetic properties, with compulsive hot bathing as a hallmark behavior.

Read this if you experience cyclic vomiting and use cannabis regularly, or if you are a clinician seeing patients with unexplained nausea.

Three opposing cannabinoids may explain the anti-emetic paradox

What the researchers found

The review synthesized existing knowledge about cannabinoid hyperemesis syndrome (CHS), describing a paradox: cannabis is well-established as an anti-emetic, yet chronic use could cause severe cyclic vomiting.

The clinical course was divided into three phases. The prodromal phase involved morning nausea and fear of vomiting. The hyperemetic phase featured severe nausea, vomiting, and abdominal pain, typically ceasing within 48 hours. The recovery phase saw symptom resolution with cannabis cessation.

Compulsive hot bathing was identified as a learned behavior that provided temporary symptom relief, with patients often spending hours in hot water. The mechanism remained unknown, though the review discussed opposing effects of THC, CBD, and cannabigerol on the emesis response.

CHS was frequently misdiagnosed due to overlapping symptoms with cyclic vomiting syndrome, leading to unnecessary diagnostic workups.

Why it matters

The comprehensive characterization of CHS phases, hallmark features, and differential diagnosis helped clinicians recognize and diagnose the condition more efficiently, potentially reducing unnecessary testing.

The numbers in context

Three phases identified: prodromal, hyperemetic (ceases within 48 hours), recovery. Three cannabinoids with opposing emesis effects: THC, CBD, cannabigerol.

How the study worked

Narrative review synthesizing case reports, clinical series, and pathophysiological hypotheses about cannabinoid hyperemesis syndrome.

What this study cannot tell us

Knowledge was largely based on case reports and small series. Mechanism remained unknown. Epidemiology was poorly characterized. No validated diagnostic criteria existed at the time.

How to read the evidence

Comprehensive narrative review synthesizing available case literature and pathophysiological hypotheses.

When this study was published

Published in 2011. CHS is now widely recognized in emergency medicine with updated diagnostic criteria.

The bigger picture

CHS represented a growing clinical challenge as cannabis use increased. The paradox of an anti-emetic drug causing vomiting highlighted the complexity of cannabinoid pharmacology with chronic use.

Questions still open

What is the mechanism by which chronic cannabis exposure switches from anti-emetic to pro-emetic? How common is CHS among chronic cannabis users?

Common questions

How can cannabis cause vomiting if it's used to treat nausea?

The review described this paradox. Cannabis contains multiple cannabinoids (THC, CBD, cannabigerol) with opposing effects on vomiting. With chronic use, the balance may shift toward pro-emetic effects through an unknown mechanism.

How is CHS diagnosed?

CHS is characterized by chronic cannabis use, cyclic nausea/vomiting episodes, compulsive hot bathing, and symptom resolution with cannabis cessation. It is often confused with cyclic vomiting syndrome and diagnosed only after extensive workups.

Read the original research

Cannabinoid hyperemesis syndrome.

Current drug abuse reviews, 4(4), 241-9

View on PubMed ↗

Citation

Galli, Jonathan A; Sawaya, Ronald Andari; Friedenberg, Frank K. (2011). Cannabinoid hyperemesis syndrome.. Current drug abuse reviews, 4(4), 241-9.