Efficacy and transdermal absorption of permethrin in scabies patients.

The clinical efficacy and transdermal absorption of permethrin, a new synthetic insecticide was investigated in ten scabies patients. All patients were successfully treated with one application of a cream, containing 5% permethrin. Apart from mild postscabies dermatitis no side-effects were observed. The mean weight of cream used per patient was 25 g (range 21-32; mean content of permethrin 1250 mg). The degree of permethrin absorption was assessed indirectly by determination of conjugated and unconjugated cis- and trans-CVA (a metabolite of permethrin) excretion in urine using two dimensional gas chromatography mass spectrometry. It was found that during the first 48 hours the mean estimated absorption was 6 mg (range 3-11), which is approximately 0.5% of the total dose.