Topical capsaicin for the treatment of cannabinoid hyperemesis syndrome, a systematic review and meta-analysis

Am J Emerg Med. 2021 May;43:35-40. doi: 10.1016/j.ajem.2021.01.004. Epub 2021 Jan 15.


Introduction: Cannabinoid hyperemesis syndrome (CHS) is a condition that is being recognized and treated more frequently in emergency departments (EDs) across the United States. Currently, ED providers rely on antiemetics, antipsychotics and benzodiazepines to alleviate the symptoms. Topical capsaicin, a transient receptor potential vanilloid 1 (TRPV1) agonist, has been proposed in recent years as a low-cost and effective alternative to the traditional antiemetic regimen when treating CHS. The aim of this systematic review and meta-analysis is to demonstrate the reliability and the gaps of what is known about this treatment modality.

Methods: Articles were extracted from PubMed, SCOPUS, and Google Scholar databases. Publication dates ranged from the inception of the databases to October 2020. Initial searches found 328 studies. After careful review and screening by two investigators, 7 studies met the inclusion criteria and were included for our meta-analysis. Variables that were evaluated included the prevalence of hospital admissions for patients treated with capsaicin, time to relief of symptoms after capsaicin administration, and ED length of stay (LOS). I-square and Q-statistic values were used to assess heterogeneity.

Results: Among the 7 studies, there was a total of 106 patients. Two studies reported time to resolution of symptoms following capsaicin administration and ED LOS. Means for these outcomes were 325 (95% CI 234-787) and 379 (95% CI 10-747) minutes respectively. I-square was 44%, and Q-statistic was 11 with 6 degrees of freedom, with a p-value of 0.1.

Discussion: With acceptable time to resolution of symptoms after topical administration and ED LOS, capsaicin appears to be an effective treatment option for symptomatic relief of CHS. Further randomized controlled trials should be conducted to examine if it is the more efficacious and efficient treatment for CHS across various care settings.

Keywords: Cannabinoid hyperemesis syndrome; Capsaicin; Emergency department; Length of stay.

Publication types

  • Meta-Analysis
  • Systematic Review

MeSH terms

  • Administration, Topical
  • Adult
  • Cannabinoids / adverse effects*
  • Capsaicin / administration & dosage*
  • Emergency Service, Hospital
  • Female
  • Hospitalization / statistics & numerical data
  • Humans
  • Male
  • Sensory System Agents / administration & dosage*
  • Syndrome
  • Vomiting / chemically induced*
  • Vomiting / drug therapy*


  • Cannabinoids
  • Sensory System Agents
  • Capsaicin