PERMETHRIN

Permethrin is a pyrethroid, a group of effective insecticides with low mammalian toxicity, originally developed from natural pyrethrum extracted from pyrethrum flowers (Chrysanthemum cinerariaefolium, Compositae). Permethrin is rapidly absorbed across the insect cuticle and exerts its action on the sodium channels of louse nerve axons, causing initial excitement followed by paralysis.

How is it used?

Permethrin crème rinse is applied over the entire scalp after the hair has been shampooed and towel dried. It is left on the hair for 10 minutes before rinsing thoroughly with water and then drying. The manufacturer states that 97-99 per cent of individuals are successfully treated at the first application, but a follow-up treatment after a week is probably a sensible precaution.