Cannabinoids for nausea and vomiting related to chemotherapy: Overview of systematic reviews

Nausea and vomiting are common and distressing adverse events of chemotherapy. This review focuses on the findings and quality of systematic reviews (SRs) of cannabinoids for chemotherapy-induced nausea and vomiting (CINV). Review of SRs, a systematic literature search, was conducted in several electronic databases and included SRs evaluating cannabinoids for CINV in cancer patients. Methodological quality and quality of reporting were evaluated by AMSTAR and PRISMA, respectively. Initial search retrieved 2,206 records, and 5 SRs were included. On the basis of findings of the sole SR judged as high methodological quality, cannabinoids seem to be more effective than placebo, equal to prochlorperazine for reducing CINV, and to be preferred by patients. The response to different combinations of antiemetic agents seems to be equal to 1 antiemetic alone. The average of AMSTAR score was 5, and the average of PRISMA score was 13.2. Cannabinoids represent a valuable option for treating CINV, despite the adverse events related to treatment, such as drowsiness and cognitive impairment. There is no good quality evidence to recommend or not the use of cannabinoids for CINV. More studies are still needed to evaluate the effectiveness of cannabinoids when compared with modern antiemetics.