A multicenter, cluster-randomized, controlled trial «Chosidow O, Giraudeau B, Cottrell J, Izri A, Hofmann R, Mann SG, Burgess I. Oral ivermectin versus malathion lotion for difficult-to-treat head lice. N Engl J Med 2010 Mar 11;362(10):896-905. »1 included 812 subjects from 376 households. Oral ivermectin (at a dose of 400 µg per kilogram of body weight) was compared with 0.5% malathion lotion, each given on days 1 and 8, for patients with live lice not eradicated by topical insecticide used 2 to 6 weeks before enrollment. In the intention-to-treat population, 95.2% of patients receiving ivermectin were lice-free on day 15, as compared with 85.0% of those receiving malathion (absolute difference, 10.2 percentage points; 95% CI, 4.6 to 15.7). In the per-protocol population, 97.1% of patients in the ivermectin group were lice-free on day 15, as compared with 89.8% of those in the malathion group (absolute difference, 7.3 percentage points; 95% CI, 2.8 to 11.8). There were no significant differences in the frequencies of adverse events between the two treatment groups.
Comment: The quality of evidence is downgraded by imprecise results (few patients and wide confidence intervals).