Levonantradol: a synthetic cannabinoid in the treatment of severe chemotherapy-induced nausea and vomiting resistant to conventional anti-emetic therapy.

Twenty-three patients with severe nausea and vomiting refractory to conventional anti-emetic therapy were entered into an open phase II study of levonantradol. Of 22 patients evaluable for response, three achieved complete relief from nausea and vomiting, seven obtained very good relief from nausea and vomiting, four obtained a partial reduction in nausea and vomiting, and eight obtained no relief. However all patients experienced side effects including, in particular, drowsiness and thought disturbance, and as a result eight patients had to be withdrawn from the study. There was no statistical patient preference for levonantradol over previous anti-emetic treatment. Levonantradol is an effective anti-emetic in approximately 50% of patients resistant to conventional anti-emetics; however, its usefulness is likely to be restricted by side effects which are common and frequently unpleasant.