title: Head lice and the use of spinosad.
abstract: BACKGROUND
  Head lice infestations are responsible for social and economic distress. Despite a reported increase in resistance, permethrin 1% is still the first-line treatment of head lice. Alternative topical pediculicidal agents include malathion and benzyl alcohol, but resistance is of growing concern. In 2011, a new pediculicide, spinosad, was introduced.
  
  
  OBJECTIVE
  Our aim was to review the clinical pharmacology, efficacy, tolerability, and current place in therapy of spinosad for the treatment of head lice.
  
  
  METHODS
  Pertinent articles and abstracts were identified through searches of MEDLINE/Ebsco and MEDLINE/Ovid from 1948 to September 2011 and International Pharmaceutical Abstracts from 1966 to September 2011.
  
  
  RESULTS
  Two reports described 3 trials of spinosad used for the treatment of head lice. One study (n = 120) demonstrated efficacy of both spinosad 0.5% and spinosad 1% compared with placebo, with 82.5% and 86.1% of patients free of live lice 14 days after treatment, respectively, compared with 25.6% in the placebo group (P < 0.001 for each treatment). The difference between the spinosad 0.5% and 1% treatment groups was not significant. Two trials (n = 1038) comparing spinosad 0.9% with permethrin 1% reported greater efficacy for spinosad with absence of live lice 14 days after 1 or 2 treatments for 84.6% and 86.7%, respectively, of primary cases compared with 44.9% and 42.9% with permethrin (P < 0.001 for both studies). The most common reported adverse events were eye and scalp irritation, but they were not statistically significant (P = 0.329 and P = 0.395, respectively). Only application-site erythema reactions showed statistical significance, with 6.8% in the permethrin group versus 3.1% in the spinosad group (P = 0.007).
  
  
  CONCLUSIONS
  Although limited, the available literature suggests that spinosad is an effective and well-tolerated agent for the treatment of head lice. In a time of increasing resistance, spinosad has demonstrated superior performance compared with permethrin. A review of the literature did not identify any studies comparing spinosad to benzyl alcohol 5% or malathion 0.5%.
authors.affiliation: Arnold & Marie Schwartz College of Pharmacy and Health Sciences, Long Island University, Brooklyn, New York, USA.
authors.forename: Susan C
authors.initials: SC
authors.lastname: Villegas
authors.forename: Robin L
authors.initials: RL
authors.lastname: Breitzka
mesh_terms: D000818:Animals; D004338:Drug Combinations; D016527:Drug Costs; D006801:Humans; D007306:Insecticides / Q000008:administration & dosage / Q000009:adverse effects / Q000191:economics / Q000493:pharmacokinetics / Q000627:therapeutic use*; D010373:Lice Infestations / Q000188:drug therapy* / Q000191:economics; D018942:Macrolides / Q000008:administration & dosage / Q000009:adverse effects / Q000191:economics / Q000493:pharmacokinetics / Q000627:therapeutic use*; D010374:Pediculus / Q000187:drug effects*; D012536:Scalp Dermatoses / Q000188:drug therapy* / Q000191:economics; D016896:Treatment Outcome
chemical_list: D004338:Drug Combinations; D007306:Insecticides; D018942:Macrolides; C415329:spinosad