New topical suspension approved to treat head lice

The FDA has approved Natroba Topical Suspension 0.9% for treating head lice in patients 4 years of age and older.

The active ingredient in Natroba is spinosad, which is derived from fermentation of a soil actinomycete bacterium, Saccharopolyspora spinosa.

Approval was based on 2 multicenter, randomized, active-controlled trials involving 1,038 patients with head lice. Some 552 patients received treatment with Natroba, whereas the rest were treated with permethrin 1%. Efficacy was evaluated in the youngest patient from each household (primary patients), and safety was evaluated in other members of the household (secondary patients). In the first study, 91 primary patients received Natroba, and 89 received permethrin 1%. In the second study, 83 primary patients were treated with Natroba, and 84 were treated with permethrin 1%. After initial treatment, patients were reevaluated on day 7. Those with any live lice were retreated.

The proportion of Natroba-treated patients who were free of lice after 14 days after their final treatment was 84.6% (n=77) in the first study and 86.7% (n=72) in the second study. In comparison, the percentage of patients treated with permethrin 1% and free of lice was 44.9% (n=40) and 42.9% (n=36), respectively. Most Natroba-treated patients needed only 1 treatment, whereas permethrin 1%-treated patients required 2 treatments.

In clinical trials, the most common adverse effects associated with Natroba use are application-site redness (3%) and redness and irritation of the eyes (2%).

Labeling warns that the product, which contains benzyl alcohol, is not recommended for use in infants younger than 6 months of age. Systemic exposure to benzyl alcohol has been linked to serious adverse effects and death in low-birth-weight infants and neonates. This prescription product should be used in conjunction with an overall lice management program.

FDA. FDA approves head lice treatment for children and adults [press release]. January 18, 2011. www.fda.gov/newsevents/newsroom/pressannouncements/ucm240302.htm. Accessed January 27, 2011.