Numerous animal models support the suggestion that THC and CBD have anti-emetic and anti-nausea properties (1). At present, robust human data remains limited due to the lack of large scale, controlled clinical trials. Anecdotal evidence, surveys and clinical trials investigating nausea in HIV/AIDS patients and chemotherapy induced nausea and vomiting (CINV) patients, indicate that cannabinoid medicine may assist in the control of nausea. In a recent survey performed by 271 patients in Canada who are registered to purchase cannabis from Tilray, 29% (n = 79) reported using cannabis for nausea. Furthermore, cannabis was perceived to be effective for symptom relief in nearly all of the total participants (n = 257, 95%) (2).
In a systematic review of 30 clinical trials involving orally administered synthetic cannabinoids (nabilone and dronabinol) for the treatment of CINV, cannabinoids were found to be more effective than active comparators (prochlorperazine, metoclopramide, chlorpromazine, thiethylperazine, haloperidol, domperidone, or alizapride) and placebo across all trials (3). In the Duran et al study, a higher proportion of patients in the cannabis based medicine (CBM) group experienced a complete response during the overall observation period [5/7 (71.4%) with CMB vs. 2/9 (22.2%) with placebo, the difference being 49.2% (95% CI 1%, 75%)], due to the delayed period (4). Furthermore, 3 products based on synthetic cannabinoids (nabilone and dronabinol) have already received FDA approval in the USA for the treatment of CINV in patients who have failed to respond adequately to conventional antiemetic treatment. Cannabinoids have also been recommended in international anti-emetic guidelines for the prevention of chemotherapy-induced nausea and vomiting (5).
In a study of healthy volunteers in which syrup of ipecac was used to induce nausea and vomiting, smoked marijuana was found to reduce subjective ratings of queasiness and objective measures of vomiting (6).
Patients suffering from HIV also report using medicinal cannabis to alleviate nausea and vomiting symptoms. In a survey of 523 HIV patients, 27% reported using cannabis to treat their symptoms, 93% of which report an improvement in nausea with cannabis use (7).
Two recent studies investigating the efficacy of THC in preventing postoperative nausea and vomiting found THC or nabilone (synthetic THC) to not be an effective treatment for nausea under the trial conditions tested (8-9).
Safety of an oromucosal standardized cannabis extract in chemotherapy-induced nausea and vomiting (4)
Study Design: Double-blind, pilot, parallel, placebo-controlled phase II clinical trial
Inclusion Criteria: Participants had to be older than 18 years, Karnofsky score 70 with CINV lasting more than 24h according to the MANE questionnaire, despite prophylaxis with standard anti-emetic treatment.
Cohort: Whole plant cannabis-based medicine (CBM) n = 7. Placebo n= 9.
Results: A higher proportion of patients in the CBM group experienced a complete response during the overall observation period [5/7 (71.4%) with CMB vs. 2/9 (22.2%) with placebo, the difference being 49.2% (95% CI 1%, 75%)], due to the delayed period.
Safety: The incidence of AEs was higher in the CBM group (86% vs. 67%). No serious AEs were reported. Only one patient in the CBM arm was withdrawn due to AEs.