Topical capsaicin helped more CHS patients in the emergency department than standard treatment alone | Research

The takeaway

Among 201 patients with cannabinoid hyperemesis syndrome, 55% who received topical capsaicin achieved symptom relief with minimal rescue medication compared to 21% without capsaicin.

Emergency medicine physicians treating CHS and patients experiencing cannabinoid hyperemesis.

55% achieved relief with capsaicin vs. 21% without

What the researchers found

A significantly greater proportion of patients receiving capsaicin achieved efficacy (55% vs. 21%, p<0.001). Time to discharge after treatment was shorter in the capsaicin group (3.72 vs. 6.11 hours, p=0.001). However, capsaicin did not reduce total medications received or total ED length of stay, suggesting it may work best as a first-line treatment rather than a rescue add-on.

Why it matters

CHS is increasingly common and notoriously difficult to treat in the ED. Capsaicin cream applied to the abdomen is cheap, low-risk, and appears to provide meaningful symptom relief, potentially reducing ED stays and the need for multiple antiemetics.

The numbers in context

201 patients (25 pediatric). Capsaicin efficacy: 55% vs. 21% without (p<0.001). Time to discharge: 3.72 vs. 6.11 hours (p=0.001). No difference in total medications or total ED length of stay.

How the study worked

Single-center retrospective cohort study of 201 patients (25 pediatric) with suspected or confirmed CHS presenting to the ED. Compared outcomes between patients who received topical capsaicin and those who did not. Primary outcome: requiring one or fewer rescue medications after treatment.

What this study cannot tell us

Retrospective design. Non-randomized treatment assignment. Single center. CHS diagnosis was clinical (no biomarker). Cannot control for which patients received capsaicin vs. not.

How to read the evidence

Moderate-sized retrospective study. Consistent with smaller reports but non-randomized design limits conclusions.

When this study was published

2021 retrospective study from a single ED.

The bigger picture

The biological rationale involves TRPV1 receptors, which capsaicin activates and which are also involved in cannabinoid signaling. The finding that capsaicin works better early in the ED course (before multiple medications) supports using it as a first-line approach.

Questions still open

Would capsaicin show even stronger effects if given immediately upon CHS diagnosis? What is the optimal capsaicin concentration and application area? Would a randomized trial confirm these findings?

Common questions

How does capsaicin work for CHS?

Capsaicin activates TRPV1 receptors in the skin, which are connected to the same pathways involved in cannabinoid-induced nausea and vomiting. Applied to the abdomen, it appears to provide symptomatic relief.

Should capsaicin be used first or as a backup?

The data suggest it works better when given early. The authors recommend future research on using capsaicin upon initial CHS diagnosis before adding other medications.

Read the original research

Efficacy of topical capsaicin for cannabinoid hyperemesis syndrome in a pediatric and adult emergency department.

The American journal of emergency medicine, 49, 343-351

View on PubMed ↗Publisher’s paper ↗

Citation

Kum, Vivian; Bell, Adrienne; Fang, Wei; VanWert, Elizabeth. (2021). Efficacy of topical capsaicin for cannabinoid hyperemesis syndrome in a pediatric and adult emergency department.. The American journal of emergency medicine, 49, 343-351. https://doi.org/10.1016/j.ajem.2021.06.049