Capsaicin was beneficial in all CHS case reports and series (18 patients total), but two retrospective cohort studies found no significant benefit on ER length of stay.
Emergency physicians, pharmacists, and cannabis users experiencing CHS.
Cohort studies showed no benefit
What the researchers found
Five full-text articles and 6 conference abstracts were included. Case reports and series (n=18 patients) found capsaicin effective for CHS. However, both retrospective cohort studies failed to find significant benefits for capsaicin on ER length of stay as primary outcome.
Why it matters
Capsaicin is recommended as first-line CHS treatment in some guidelines, but this review reveals the evidence behind that recommendation is essentially case reports. The two studies with better designs found no benefit.
The numbers in context
241 articles screened; 11 included; 18 patients in case reports/series all showed benefit; 2 retrospective cohort studies found no significant improvement in ER length of stay.
How the study worked
Systematic review searching MEDLINE, CINAHL, and EMBASE through March 2019. Included 5 full-text articles (3 case reports, 2 case series) and 6 conference abstracts (1 case report, 3 case series, 2 retrospective cohorts).
What this study cannot tell us
All evidence is low methodological quality. Publication bias likely (positive case reports more likely published). No randomized trials exist. Capsaicin dosing and application varied across studies.
How to read the evidence
Preliminary: systematic review constrained by uniformly low-quality included studies.
When this study was published
Published in 2019.
The bigger picture
The disconnect between positive case reports and negative cohort studies is a cautionary tale for evidence-based medicine. Capsaicin may still help individual patients, but the evidence does not support routine first-line use.
Questions still open
- Would a randomized trial of capsaicin for CHS settle the question? How does capsaicin compare to droperidol or benzodiazepines for CHS?
Common questions
Does capsaicin cream work for CHS?
Why is capsaicin used for CHS?
Read the original research
Efficacy of Capsaicin for the Treatment of Cannabinoid Hyperemesis Syndrome: A Systematic Review.
The Annals of pharmacotherapy, 53(11), 1145-1152
Citation
McConachie, Sean M; Caputo, Ryan A; Wilhelm, Sheila M; Kale-Pradhan, Pramodini B. (2019). Efficacy of Capsaicin for the Treatment of Cannabinoid Hyperemesis Syndrome: A Systematic Review.. The Annals of pharmacotherapy, 53(11), 1145-1152. https://doi.org/10.1177/1060028019852601
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