Schussel, V., Kenzo, L., Santos, A., Bueno, J., Yoshimura, E., de Oliveira Cruz Latorraca, C., . . . Riera, R. (2017). Cannabinoids for nausea and vomiting related to chemotherapy: Overview of systematic reviews. Phytotherapy Research, 32, 567–576.

STUDY PURPOSE: To present the findings and conduct a critical appraisal of systematic reviews focusing on the effects of cannabinoids as a treatment for nausea and vomiting in patients with cancer during chemotherapy.

TYPE OF STUDY: Meta analysis and systematic review

DATABASES USED: EMBASE, PEDro, CINAHL, Cochrane Database of Systematic Reviews, LILACS, Medline, PsycINFO

YEARS INCLUDED: 2001 to 2015

INCLUSION CRITERIA: RCTs only, SRs focusing exclusively on cannabinoids for the treatment of CINV

EXCLUSION CRITERIA: Studies registered in PROSPERO and not completed or published by the date of search

TOTAL REFERENCES RETRIEVED: 2,206

EVALUATION METHOD AND COMMENTS ON LITERATURE USED: AMSTAR and PRISMA. Average AMSTAR score was 5, with low of 1 and high of 11. Max score of 11. Average PRISMA score was 13.2, ranging from 1 to 25. Max score of 27.

FINAL NUMBER STUDIES INCLUDED: 5 

TOTAL PATIENTS INCLUDED IN REVIEW: Not included 

KEY SAMPLE CHARACTERISTICS: Participants presenting nausea and/or vomiting attributed to any type of chemotherapy for cancer. Treatment included: THC, nabilone, dronabinol, and levonantradol compared to any pharmacologic or nonpharmacologic intervention.

PHASE OF CARE: Not specified or not applicable

Cannabinoids seem to be superior to placebo and equal to prochlorperazine in reducing nausea and vomiting, and, in general, are similar to standard antiemetics alone or in combination. Patient-reported outcomes indicated that patients tend to prefer cannabinoids over placebo and other antiemetics, but cannabinoids have a higher rate of adverse events when compared to traditional antiemetics.

Cannabinoids may be considered a therapeutic option for treating CINV. However, it is unclear from this analysis where cannabinoids are superior to traditional antiemetics in effectiveness or safety. There is a shortage of high-quality evidence to clarify these questions.

• Limited number of studies included
• Mostly low quality/high risk of bias studies

Cannabinoids may be effective and superior to placebo to treat CINV. Although adverse events were more frequent in patients treated with cannibinoids, patients preferred cannibinoids over other antiemetics. More studies are needed to evaluate the effectiveness and safety of cannabinoids in CINV.