Oral Ivermectin Proves Superior to Insecticide for Treating Head Lice


BERLIN — Oral ivermectin proved superior to conventional therapy with malathion lotion for the treatment of difficult to eradicate head lice infestations in a large multinational randomized trial.

The number needed to treat—that is, the number of patients who needed to be treated with two doses of oral ivermectin 1 week apart instead of two applications of topical malathion in order for one additional patient to become louse-free—was 9.8, Dr. Olivier Chosidow reported at the annual congress of the European Academy of Dermatology and Venereology.

“Our randomized trial suggests strongly that ivermectin could be valuable, at least in patients who've previously failed standard therapy because their head lice aren't sensitive enough to local insecticides,” said Dr. Chosidow of the University of Paris.

He reported on 812 patients with head lice infestation in 376 randomized households. All participants were at least 2 years old and weighed at least 15 kg. At enrollment, all had live head lice detected by combing which had not been eradicated by topical insecticide therapy 2–6 weeks earlier. The households were randomized to double-blind/double-placebo supervised treatment with two single doses of oral ivermectin (Stromectol, Mectizan) at 400 mcg/kg or 0.5% malathion lotion, both administered on days 1 and 8.

The primary study end point was the absence of head lice upon inspection by combing on day 15. The success rate was 95% in the ivermectin group, compared with 85% in the malathion group. The secondary end points were the absence of head lice on days 2, 8, 22, and 29. The ivermectin group fared significantly better at each time point.

Generally mild treatment-related adverse events were noted in 7.5% of the ivermectin group and 10.9% who received malathion. There were no serious adverse events. It is well-established that ivermectin does not cross the human blood/brain barrier, according to Dr. Chosidow. Families appreciated the convenience of oral therapy.

Oral ivermectin is not approved by the Food and Drug Administration for the treatment of pediculosis. However, the Centers for Disease Control and Prevention guidelines recommend it for the treatment of scabies as an alternative to first-line topical 5% permethrin.

Dr. Erwin Tschachler, EADV secretary-general elect, singled out Dr. Chosidow's study as one of the infectious disease highlights of the congress.

“This is the first time an oral therapy for this parasitic infestation has been successful,” commented Dr. Tschacler, head of the research division for biology and pathobiology of the skin at the University of Vienna Medical School.

Although head lice are associated with low socioeconomic status, no socioeconomic stratum is immune to infestation, and outbreaks are a growing problem in many European countries, he added.

Dr. Chosidow received a research grant from Johnson & Johnson, which sponsored the ivermectin study.

'Ivermectin could be valuable, at least in patients who've previously failed standard therapy.'

Source Dr. Chosidow

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