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

Int J Dermatol. 2013 Jan;52(1):106-12. doi: 10.1111/j.1365-4632.2012.05629.x.


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.

Trial registration: NCT00857948.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Administration, Topical
  • Adolescent
  • Adult
  • Animals
  • Child
  • Child, Preschool
  • Dose-Response Relationship, Drug
  • Female
  • Humans
  • Insecticides / administration & dosage*
  • Insecticides / adverse effects
  • Ivermectin / administration & dosage*
  • Ivermectin / adverse effects
  • Lice Infestations / drug therapy*
  • Male
  • Middle Aged
  • Pediculus / pathogenicity*
  • Pruritus / chemically induced
  • Scalp
  • Scalp Dermatoses / chemically induced
  • Treatment Outcome
  • Young Adult


  • Insecticides
  • Ivermectin

Associated data