Oral levonantradol in the treatment of chemotherapy-induced emesis: preliminary observations.

Levonantradol, a new synthetic cannabinoid, was examined for antiemetic effectiveness in 27 patients with refractory chemotherapy-induced emesis. Thirty-one courses of levonantradol were administered orally beginning 2 hours before chemotherapy and continuing every 4 hours for a minimum of 12 to 24 hours at one of three different dose levels. At the 0.5-mg dose, 14 patients were evaluable with seven partial response (50 per cent) and one complete response (7 per cent). At the 1.0-mg dose, 11 patients were evaluable with five partial responses (45 per cent) and three complete responses (27 per cent). Only one patient has thus far been treated at the 1.5-mg dose with no response noted. Side effects observed included somnolence (90 per cent), dry mouth (83 per cent), dizziness (67 per cent), decreased concentration (40 per cent), dysphoria (33 per cent), and altered perception (30 per cent). Euphoria ("high") was infrequent (9 per cent). No relationship between dose (0.5 and 1.0 mg) and side effects was observed. There was a suggestion of improved antiemetic efficacy at the 1.0-mg dose. Although this study is preliminary, it appears that levonantradol is a relatively well-tolerated oral antiemetic that deserves further evaluation.