Systematic review finds capsaicin data for CHS is promising but low quality

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.

McConachie, Sean M et al.·The Annals of pharmacotherapy·2019·Preliminary EvidenceSystematic Review
RTHC-02168Systematic ReviewPreliminary Evidence2019RETHINKTHC RESEARCH DATABASErethinkthc.com/research

Quick Facts

Study Type
Systematic Review
Evidence
Preliminary Evidence
Sample
N=18

What This Study 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.

Key Numbers

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 They Did This

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).

Why This Research 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 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.

What This Study Doesn't 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.

Questions This Raises

  • ?Would a randomized trial of capsaicin for CHS settle the question?
  • ?How does capsaicin compare to droperidol or benzodiazepines for CHS?

Trust & Context

Key Stat:
Cohort studies showed no benefit
Evidence Grade:
Preliminary: systematic review constrained by uniformly low-quality included studies.
Study Age:
Published in 2019.
Original Title:
Efficacy of Capsaicin for the Treatment of Cannabinoid Hyperemesis Syndrome: A Systematic Review.
Published In:
The Annals of pharmacotherapy, 53(11), 1145-1152 (2019)
Database ID:
RTHC-02168

Evidence Hierarchy

Meta-Analysis / Systematic ReviewCombines many studies into one answer
This study
Randomized Controlled Trial
Cohort / Case-Control
Cross-Sectional / Observational
Case Report / Animal Study

Analyzes all available research on a topic using a structured method.

What do these levels mean? →

Frequently Asked Questions

Does capsaicin cream work for CHS?

Case reports say yes (18/18 patients improved), but two retrospective studies with more patients found no significant benefit on ER stay duration. The evidence quality is low overall.

Why is capsaicin used for CHS?

Capsaicin activates TRPV1 receptors, which overlap with cannabinoid receptor pathways in the gut. It mimics the relief patients get from hot showers, which also activate TRPV1 receptors.

Read More on RethinkTHC

Cite This Study

RTHC-02168·https://rethinkthc.com/research/RTHC-02168

APA

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

MLA

McConachie, Sean M, et al. "Efficacy of Capsaicin for the Treatment of Cannabinoid Hyperemesis Syndrome: A Systematic Review.." The Annals of pharmacotherapy, 2019. https://doi.org/10.1177/1060028019852601

RethinkTHC

RethinkTHC Research Database. "Efficacy of Capsaicin for the Treatment of Cannabinoid Hyper..." RTHC-02168. Retrieved from https://rethinkthc.com/research/mcconachie-2019-efficacy-of-capsaicin-for

Access the Original Study

Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.

This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.