New treatment for lice is highly effective, study reports

Los Angeles Times

A topical formulation of ivermectin, a medication for roundworm, eradicated lice infestations in almost three-quarters of children who coated their dry hair with the lotion once for 10 minutes -- a level of effectiveness that’s on a par with new lice treatments that require two applications, a new study has found.

The new medication, approved by the FDA earlier this year, appears both to kill lice and to cause their larvae to die as soon as they hatch, and required no “nitpicking” -- the painstaking hunt for eggs left behind. That results in a prompt end to an infestation that can cause children and their families acute social and physical discomfort, as well as several missed days of school. Among subjects in the trial who got the ivermectin, 73.8% were free of lice two weeks after treatment.

The study, underwritten by Topaz Pharmaceuticals, the maker of the topical formulation marketed as Sklice, appeared this week in the New England Journal of Medicine.

Children who come home from school or camp with the itchy scalp and tiny biting parasites have several treatments available to control the infestation. But in recent years, some of those -- including the front-line treatment permethrin and pyrethrins -- have grown less effective, as lice have grown resistant to their killing powers. The second-line treatment lindane may pose safety issues when used on kids under 110 pounds, and the pesticidal treatment malathion, which smells awful and must stay on the hair eight to 12 hours, has not been shown safe for very young children.


In the past three years, the Food and Drug Administration has approved two new lice treatments -- benzyl alcohol lotion (marketed as Ulesfia) and spinosad suspension (marketed as Natroba).

The latest study did not compare ivermectin with any of the existing treatments, but against a placebo version of the lotion. Experts say that head-to-head comparisons of the existing treatments need to be made to determine which ones doctors should turn to first, and which should be held back for tougher cases or special populations.