A randomized, assessor-blind, parallel-group, multicentre, phase IV comparative trial of a suffocant compared with malathion in the treatment of head lice in children

Australas J Dermatol. 2010 Aug;51(3):175-82. doi: 10.1111/j.1440-0960.2010.00622.x.


Background/objectives: There are concerns about the effectiveness of head lice treatments because of increasing resistance and safety. This trial compared the safety and efficacy of a suffocant-based head lice treatment to malathion in children.

Methods: The trial used strict entry criteria, standardized treatment and assessment regimens, sibling treatment where appropriate and a primary efficacy end-point defined as the absence of live head lice.

Results: A total of 216 children were enrolled. One hundred and sixty-nine were per-protocol. The suffocant was significantly more effective than malathion for the intention-to-treat population (53.9% vs 40.4% louse-free, unadjusted P = 0.052; adjusted P = 0.024), as well as for the per-protocol population (57.8% vs 43.0% louse-free, unadjusted P = 0.054; adjusted P = 0.045). Adverse events were limited to itching or stinging and there were no serious or systemic adverse events. Repeat insult patch testing with the suffocant resulted in no adverse reactions. In vitro tests confirmed that the suffocant is a potent ovicide and pediculicide with 100% mortality of eggs and lice following a 20-min contact time.

Conclusions: The suffocant is shown to be significantly more effective in eliminating head lice than malathion in children, while being associated with a low incidence of mild, transient adverse events.

Publication types

  • Clinical Trial, Phase IV
  • Multicenter Study
  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Aged
  • Animals
  • Asphyxia / chemically induced
  • Child
  • Child, Preschool
  • Exanthema / chemically induced
  • Female
  • Humans
  • Insecticides / therapeutic use*
  • Lice Infestations / drug therapy*
  • Malathion / adverse effects
  • Malathion / therapeutic use*
  • Male
  • Middle Aged
  • Pediculus / drug effects*
  • Scalp / drug effects
  • Single-Blind Method
  • Treatment Outcome
  • Young Adult


  • Insecticides
  • Malathion