Permethrin

Permethrin cream contains permethrin, a pyrethroid compound used topically to treat infestation with Sarcoptes scabiei (scabies). It works on the nerve cell membrane of the parasite, disrupting the sodium channel current that normally regulates the membrane's polarization. This disturbance delays repolarization and leads to paralysis of the mites.

Pharmacokinetics: Topical application is the only approved route of administration, and human data on systemic exposure or kinetics after skin application remain limited. Some metabolism takes place in the skin before absorption. Less than 0.5% of the applied dose is absorbed within the first 48 hours. Once absorbed, permethrin is rapidly broken down through ester hydrolysis, most likely in the liver, and the resulting products are excreted mainly in the urine.