Treatment of pediculosis capitis with thiabendazole: a pilot study

Despite the improvement of health standards, head lice infestation remains a problem worldwide. In addition, there is increasing evidence that head lice are becoming resistant to common pediculocides.

To test the potential effectiveness of thiabendazole, a potent and broad-spectrum antiparasitic and scabicidal agent, for the treatment of pediculosis capitis.

Twenty-three female patients, aged 7-12 years, who had active head lice infestation, were treated with oral thiabendazole, 20 mg/kg twice daily for 1 day, with repeat treatment after 10 days.

On the 11th day, meticulous hair examination showed that 21 patients had responded to treatment [91%; 95% confidence interval (CI), 71-98%], with 14 showing complete responsiveness (61%; 95% CI, 40-78%). The only adverse reactions observed were nausea and mild dizziness, which occurred in four patients, three of whom took the drug on an empty stomach.

Thiabendazole may be a promising treatment for head lice infestation. The primary action of this drug seems to be the inhibition of parasite microtubule polymerization by binding to beta-tubulin. In addition, thiabendazole may interfere with the synaptic transmission of lice through its probable cholinergic effect. As pediculosis capitis is a very communicable disease, the unresponsiveness to thiabendazole could largely be attributed to new infestations during the drug-free interval. Therefore, massive and simultaneous rather than individual and isolated treatments should be used to achieve the epidemiologic control of this ectoparasitosis. As this is a preliminary study, the performance of double-blind, randomized controlled trials on this subject is warranted. Thiabendazole, either alone or in combination with other agents, may prove to be of particular use in areas in which head lice show resistance to common pediculocides.