
Nausea and vomiting are severe and distressing adverse effects of many chemo- and radiotherapeutic treatments. Palliative care patients also complain frequently of nausea that impairs their quality of life.
Nausea and emesis induced by chemotherapy
A systematic review is available establishing the efficacy of cannabinoids against chemotherapy-induced nausea and vomiting17. These findings were replicated in another systematic review with meta-analysis18. Thirty randomised-controlled trials were included in this review investigating oral dronabinol, oral nabilone and intramuscular levonantradol in comparison to placebo and antiemetics available in the 1980s (prochlorperazine, metoclopramide, thiethylperazine, haloperidol, domperidone, alizapride). Cannabinoids showed a significantly better control of chemotherapy-induced nausea and vomiting than placebo/control medication, and were preferred for future chemotherapy cycles by two out of three patients in cross-over trials. Benefits seemed to be more pronounced in medium emetogenic chemotherapy than in low or high emetogenic chemotherapy. However, none of the included trials tested cannabinoids against the modern forms of antiemetic prophylaxis (5-HT3-antagonists, NK1-receptor antagonists and drug combinations including glucocorticoids). The authors concluded that in selected patients, cannabinoids may be useful as mood-enhancing adjuvants for the control of chemotherapy-related sickness, but considering the availability of well-investigated modern drug combinations for antiemetic prophylaxis, cannabinoids could not be recommended for solitary or first-line use.
A recent systematic review on antiemetic medication for prevention and treatment of chemotherapy-induced nausea and vomiting in children identified four randomised controlled trials, which were not meta-analysed due to study heterogeneity19. Cochrane authors concluded that cannabinoids “are probably effective, but produce high levels of side effects” (p.14) and no clear route, schedule or dose recommendation could be identified from the included studies.
As cannabinoids act differently from other antiemetic drugs, they might be effective when administered in combination with modern antiemetics in people whose emesis is not adequately controlled with current treatment options. Plasse reports anecdotal evidence that cannabinoids might help against chemotherapy-induced delayed nausea20. One randomised, placebo-controlled trial investigated the efficacy of dronabinol alone or in combination with ondansetron for the prevention of delayed chemotherapy-induced nausea and vomiting21. Sixty-four participants receiving moderate to high emetogenic chemotherapy were randomised to one of four intervention groups. All participants received dexamethasone plus ondansetron before chemotherapy, the three active intervention groups received additional dronabinol on the day of chemotherapy and either dronabinol, ondansetron or both on the following four days after chemotherapy. Results suggested that dronabinol was equally effective as ondansetron for the prevention of delayed chemotherapy induced nausea and vomiting. Acute chemotherapy induced nausea and vomiting on the first day of chemotherapy was reduced in the three groups receiving additive dronabinol compared to the standard treatment alone (dexamethasone + ondansetron). However, this trial failed to recruit the necessary number of participants for a valid evaluation and findings need to be replicated in a larger study with comparable intervention groups at baseline to further elucidate the potential benefits of additive dronabinol.
Nausea and emesis induced by radiotherapy
One double-blind randomised cross-over trial compared nabilone and metoclopramid for the prevention of radiotherapy-induced nausea in 40 patients22. Findings suggested no difference in the antiemetic effect of 2mg nabilone compared to 30mg metoclopramid, but adverse reactions were more severe in the nabilone group.
Strasser et colleagues conducted a randomised placebo-controlled phase III trial and compared oral THC, oral cannabis extracts and placebo for patients with cancer-related anorexia23. Two hundred and forty-three adults with advanced cancer (54% men) were randomly assigned to THC/cannabidiol (2.5mg/1mg), THC alone (2.5 mg) or placebo orally daily for 6 weeks. The results showed significant unspecific (placebo) effects on symptom control, but no substance-specific benefit of cannabinoids over placebo on appetite or overall quality of life (primary study end points), or mood or nausea (secondary end points). Recruitment for this study was terminated early because of insufficient differences between study arms.
Jatoi24 tested oral dronabinol (2.5mg twice a day + placebo) versus the progesterone derivate megestrol (plus placebo) versus both agents. 469 patients with advanced cancer and weight loss participated in this double-blind randomised trial. Megestrol acetate had better outcomes (appetite, food intake, body weight) than dronabinol, while the combination was not more effective than megestrol alone.
A small placebo-controlled randomised trial investigated THC (2.5 mg/day) in 46 patients with advanced cancer25. Per-protocol analyses of 21 patients found a subjectively increased appetite and taste perception in the THC group, but no differences in total caloric intake between both groups.
Several findings suggested that oral cannabinoids increased appetite in cancer patients, stopped weight loss or even increased body weight26,27. In an open phase II study, Nelson investigated the effect of 3x2.5 mg oral THC in 19 patients with various malignancies and tumour-associated anorexia28. Thirteen of 18 patients that could be evaluated reported a subjective improvement in appetite. Body weight was measured in six patients and after four weeks was increased in three patients, not changed in two and decreased in one.
To summarise, the most recent and rigorous findings from randomised trials suggested no benefit of treatment with dronabinol/THC alone or in combination with cannabidiol for cancer-related anorexia-cachexia syndrome compared with placebo or megestrol acetate. Recent reviews on the treatment of cancer cachexia support a multimodal approach with different, newer medications29,30.
A systematic review of randomised clinical trials investigated the efficacy of cannabinoids in the management of pain31. Campbell reviewed five studies with a total of 128 cancer patients comparing oral THC or a THC congener (benzopyranopyridine) to placebo, codeine or a barbiturate. Results were contradictory and cannabinoids were found to be equally or more effective than placebo, and less or equally effective as codeine. Studies were rather small (n=10 to n=37) and dose-limitating adverse effects were a common. Reviewers concluded that there is insufficient evidence to support the introduction of cannabinoids into widespread clinical use as analgesics.
Two phase II randomised double-blind controlled trials investigated the use of cannabinoids in participants with advanced cancer32,33. Both trials used cannabinoid preparations as oral sprays in comparison to placebo sprays as add-on medication to opioids in participants with intractable cancer pain.
The first trial compared two cannabis extracts (Sativex© and Tetranabinex©) versus placebo for pain control32. A statistically significant improvement of pain (as measured in a pain score) due to cancer unresponsive to opioids was seen for Sativex©, but not for Tetranabinex© compared to placebo (177 participants).
Results of the second trial have so far only been published as a press report: Statistically significant differences from placebo in pain scores were reported for Sativex© at three different doses in this dose-finding study. A phase III trial is under way33.
Maida34 conducted a prospective observational study comparing advanced cancer patients who were treated with or without nabilone in a specialized palliative care center. 112 patients were prescribed or not prescribed nabilone at their physicians’ discretion based on the presence of physical symptoms including pain. Pain and nausea improved in the nabilone group. The uncontrolled study design, however, does not allow to causally attribute these observed findings to nabilone as they might also be related to bias or unspecific effects.
Last updated in November 2011 by Gabriele Dennert.
Fully updated and revised in November 2009 by Gabriele Dennert.
Summary first published in November 2005, authored by Gabriele Dennert.