Assessment of the safety and efficacy of three concentrations of topical ivermectin lotion as a treatment for head lice infestation.

BACKGROUND: Ivermectin is a broad-spectrum parasiticide in widespread systemic use, including as an off-label treatment for head lice infestation. The potential of the topical use of ivermectin as a treatment for head lice infestation was suggested by an in vitro report of a novel lotion formulation.
OBJECTIVES: This study investigated the relative effectiveness of three ivermectin lotion concentrations (0.15, 0.25, and 0.5%) compared with vehicle placebo in eliminating head lice infestation.
METHODS: In this randomized, blinded study, 78 head lice-infested subjects, aged 2-62 years, received a single, 10-minute application of product on day 1. Evaluations were completed at two and six hours post-application, and on days 2, 8 (±1), and 15 (+2). Safety was assessed according to the evaluations of trained observers and adverse event (AE) reports. Efficacy was assessed according to scalp and hair examinations.
RESULTS: Compared with placebo, all ivermectin concentrations resulted in the statistically significant (P ≤ 0.003) eradication of head lice through to day 15, with the highest level of eradication (73.7%) in subjects who received the 0.5% concentration. The severity of pruritus decreased from baseline in all treatment groups, including the placebo group, from six hours post-treatment to day 15, with the greatest reduction in the 0.5% concentration group. No ocular irritation was observed. All three ivermectin treatment strengths and vehicle were well tolerated.
CONCLUSIONS: A single application of a 0.5% concentration of this ivermectin lotion formulation shows promise as a safe and effective treatment for head lice infestation and the associated signs of pruritus.

RCT Entities:   Population Interventions Outcomes