Role of nabilone in CINV Figure 2b Nabilone signiﬁcantly reduces the severity of nausea throughout the chemotherapy cycle.Reproduced with permission from Einhorn LH,Nagy C,Furnas B,Williams SD. 1981. Nabilone:An effective antiemetic in patients receiving cancer chemotherapy. J Clin Pharmacol, 21(suppl):64–69. Copyright © 1981 SAGE Publications. Grading of nausea: 1 = mild; 2 = moderate; 3 = severe. prochlorperazine (p 0.001), and nausea severity declined each day patients received nabilone. The efﬁcacy of nabilone was observed with all types of chemotherapy and regardless of which order patients received the agent. Nine patients discontinued antiemetic therapy due to development of intol- erable side effects – 4 who were receiving prochlorperazine and 5 during nabilone therapy. The predominant side effects were similar with both drugs; however, the incidence was approximately doubled during nabilone therapy. Nonethe- less, a signiﬁcant (p 0.001) proportion of patients preferred nabilone over prochlorperazine (78% vs 15%). Einhorn and colleagues conducted a double-blind, randomized, cross-over study in 100 cancer patients (Einhorn et al 1981). These patients, most of whom received cisplatin-based chemotherapy for testicular cancer, received 2 mg nabilone or 10 mg prochlorperazine every 6 hours as needed during chemotherapy cycle one and crossed over to the second drug during cycle 2. Compared with the effects of prochlorperazine, nabilone significantly (p 0.001) reduced the severity and duration of nausea and frequency of vomiting. In patients receiving nabilone, the mean severity score for nausea (1 = mild, 2 = moderate, 3 = severe nausea) declined from day 1 to day 3 and remained stable thereafter at values lower than 1. With nabilone therapy, the number of vomiting episodes was reduced by about 33% on all days of chemotherapy. Of the 20 patients who failed to complete the study, only 3 withdrew due to adverse effects of nabilone. Similar to the ﬁnding from Herman and associates, patients overwhelmingly preferred nabilone over prochlorperazine (60 patients [75%] vs 17 patients [17%]). Of the 60 patients who indicated a preference for nabilone, 46 received further Therapeutics and Clinical Risk Management 2008:4(1) chemotherapy and opted to continue to receive nabilone for a total of 76 courses of chemotherapy. Results similar to those described above have also been found showing the superiority of nabilone compared to prochlorperazine in lung cancer patients undergoing chemotherapy (Ahmedazi et al 1983; Niiranen and Mattson 1985), but the side effect proﬁle of dizziness and disorientation demands careful patient monitoring. No difference was found between nabilone and metoclopramide in patients on cisplatin (Crawford and Buckman 1986), while nabilone has been found superior to alizapride in young patients with testicular cancer on cisplatin (Niederle 1986) and was superior to domperidone in another trial in which 70% of subjects were on cisplatin (Pomeroy et al 1986). Mixed results have been found comparing oral nabilone and prochlorperazine to intravenous dexamethasone and metoclopramide (Cunningham et al 1988). Nabilone has even shown to be superior to prochlorperazine for children under- going chemotherapy (Chan et al 1987). The effectiveness and tolerability of nabilone may be improved by the addition of dexamethasone (Niiranen and Mattson 1987). The results of these early studies were summarized in a 2001 systematic review of 30 studies involving cannabinoids (nabilone, 16 studies; dronabinol, 13 studies; levonantradol, 1 study) compared with placebo or active control (prochlor- perazine, metoclopramide, chlorpromazine, haloperidol, domperidone, and alizapride) for the treatment of CINV (Tramér et al 2001). Cannabinoids were more effective than either active control or placebo for the reduction of vomiting episodes and lessening of nausea severity. When compared with placebo (4 studies), the number needed to treat 103