Pharmacotherapeutic group: Medicated Shampoos. ATC code: D11AC.
The surface active cationic germicide, benzalkonium chloride, is adsorbed on to dry skin scales, which are a feature of pityriasis capitis and other seborrhoeic scalp conditions. The scales are thereby loosened and attain a net positive charge. In the presence of the anionic foaming agent, sodium lauryl ether sulfate, the dandruff scales are then levitated into the negatively charged surface of the foam, and are thus washed from the hair.
The benzalkonium chloride also acts as a mild antiseptic which improves clinical performance where the condition is exacerbated by the presence of microbes. The major site of action against micro-organisms appears to be the cell membrane, where permeability is altered.