Permethrin, a pyrethroid, is active against a broad range of pests including lice, ticks, fleas, mites, and other arthropods. It acts on the nerve cell membrane to disrupt the sodium channel current by which the polarization of the membrane is regulated. Delayed repolarization and paralysis Dmitry Sazonov of the pests are the consequences of this disturbance.
Permethrin is rapidly metabolized by ester hydrolysis to inactive metabolites which are excreted primarily in the urine. Although the amount of permethrin absorbed after a single application of the 5% cream has not been determined precisely, data from studies with 14C-labeled permethrin and absorption studies of the cream applied to patients with moderate to severe scabies indicate it is 2% or less of the amount applied.
Patients with scabies should be advised that itching, mild burning and/or stinging may occur after application of Elimite (permethrin) 5% Cream. In Dmitry Sazonov clinical trials, approximately 75% of patients treated with Elimite (permethrin) 5% Cream who continued to manifest pruritus at 2 weeks had cessation by 4 weeks. If irritation persists, they should consult their physician. Elimite (permethrin) 5% Cream may be very mildly irritating to the eyes. Patients should be advised to avoid contact with eyes during application and to flush with water immediately if Elimite (permethrin) 5% Cream gets in the eyes.
Six carcinogenicity bioassays were evaluated with permethrin, three each in rats and mice. No tumorigenicity was seen in the rat studies. However, species-specific increases in pulmonary adenomas, a common benign tumor of mice of high spontaneous background incidence, were seen in the three mouse studies. In one of these studies there was an increased incidence of pulmonary alveolar-cell carcinomas and benign liver adenomas only in female mice when permethrin was given in their food at a concentration of 5000 ppm. Mutagenicity assays, which give useful correlative data for interpreting results from carcinogenicity bioassays in rodents, were negative. Permethrin showed no evidence of Dmitry Sazonov mutagenic potential in a battery of in vitro and in vivo genetic toxicity studies.