title: High in vitro efficacy of Nyda L, a pediculicide containing dimeticone.
abstract: BACKGROUND
  The therapy of pediculosis remains a common problem in clinical practice. As resistance to commonly used chemical pediculicides is constantly increasing, there is a need for new effective compounds.
  
  
  METHODS
  The efficacy of Nyda L, a new pediculicide containing a high concentration of dimeticone, was assessed in an in vitro trial and compared with three reference products (Hedrin containing 4% dimeticone, Lyclear containing 1% permethrin, and Prioderm containing 1% malathion) and a negative control group. Head lice were collected from heavily infested patients in a resource-poor community in Northeast Brazil, where no resistance against pediculicides has been reported thus far. In each of the five groups, 50 adult fully vital lice were tested. We used a dip test (immersing head lice in the undiluted products for 3 min, washing off products after 20 min). Using predefined criteria for mortality, the lice were monitored at different points in time, for a period of 24 h.
  
  
  RESULTS
  Nyda L and Prioderm killed all head lice already after 5 min. The efficacy of Nyda L was better than of Lyclear. Lice treated with Hedrin resurrected after several hours and did not show a significantly higher mortality compared with the control group after 24 h.
  
  
  CONCLUSIONS
  Nyda L can be regarded as a very efficacious pediculicidal compound, killing all lice in vitro within 5 min.
authors.affiliation: Department of Community Health, School of Medicine, Federal University of Ceará, Fortaleza, Brazil.
authors.forename: F A S
authors.initials: FA
authors.lastname: Oliveira
authors.forename: R
authors.initials: R
authors.lastname: Speare
authors.forename: J
authors.initials: J
authors.lastname: Heukelbach
mesh_terms: D000818:Animals; D004129:Dimethylpolysiloxanes / Q000494:pharmacology*; D006203:Hair Preparations / Q000494:pharmacology*; D066298:In Vitro Techniques; D007305:Insecticide Resistance; D007306:Insecticides / Q000494:pharmacology*; D010373:Lice Infestations / Q000188:drug therapy; D008294:Malathion / Q000494:pharmacology; D010374:Pediculus / Q000187:drug effects*; D026023:Permethrin / Q000494:pharmacology; D012536:Scalp Dermatoses / Q000188:drug therapy
chemical_list: D004129:Dimethylpolysiloxanes; D006203:Hair Preparations; D007306:Insecticides; D026023:Permethrin; C501844:dimethicone; D008294:Malathion