Kill the Itch

Lice treatment with spinosad works better than other topical shampoos

/ Author:  / Reviewed by: Chris Galloway, M.D.

(RxWiki News) Your kids are well into school now, and so come the germs, snotty tissues, and creepy-crawly head lice. What do you do when your kids' get the bugs?

In a newly published study, researchers found that cream rinse treatments containing spinosad (brand name Natroba) worked better than permethrin in treating head lice.

"Ask your pharmacist about cream rinses."

Spinosad, a topical treatment for head lice that patients 4 years or older can use, combines two ingredients that paralyze and kill lice, as well as their nits, or eggs.

It's applied from the scalp to the ends of the strands when the hair is dry. Permethrin is used the same way but on wet hair.

The study, led by Catalin Popescu, MD, PhD, and Raluca Popescu, MD, PhD, in the Department of Dermatology at Carol Davila University of Medicine and Pharmacy, aimed to make participants lice-free within two weeks using the fewest number of treatments.

The study included 949 patients in 391 households who already had three or more live head lice.

Participants were divided into two groups. Half of each group received a treatment with 0.9 percent spinosad and the other permethrin.

The groups were instructed to use the treatments either once or twice and record whether they had head lice after two weeks.

They found that more than 94 percent of participants who had the spinosad treatment without combing out the nits and about 68 percent who received permethrin were louse-free by the end of the 14 days.

Using both treatments and using those treatments twice was not as effective: about 56 percent got rid of the lice after one treatment and 31 percent after two treatments.

"Spinosad, which did not require nit combing, was significantly more effective than permethrin in two studies reflecting actual-use conditions, and most spinosad-treated participants required only one application," the authors said in their report.

The authors note that the study was not done at random and didn't account for how many people within each infected household actually did have lice.

They also did not take into account how bad the infestation was on each person and whether each individual used the treatments as instructed.

And since all the participants came in with lice, they may have been more willing to receive the treatments, especially if previous attempts to get rid of the lice didn't work.

These participants may be more apt to use the treatments properly and subject the study to bias.

Catalin Popescu received travel grants from Janssen-Cilag while conducting the study, which was published in the September 2012 issue of the Archives of Dermatology.

Reviewed by: 
Review Date: 
September 27, 2012
Last Updated:
August 9, 2013