Abstract

Carbaryl is a broad-spectrum insecticide effective against lice, with little toxicity to man. It is available as a lotion (Carylderm) and a shampoo (Carylderm; New Suleo; Derbac). Carbaryl was developed because lice began to show resistance to organochlorine insecticides such as DDT and gamma benzene hexachloride (Quellada; Lorexane). It was introduced in the late 1960s particularly for the control of head lice; it is less effective against mites, and not recommended for scabies. Together with the organophosphate malathion (Prioderm lotion and shampoo; Derbac Liquid), it has contributed to the substantial reduction in the prevalence of lice in this country; in a recent survey of 12,000 school children in England, 9% had head lice.¹ Several pyrethroid compounds are also used for head lice, such as Parlice which contains bioallethrin and piperonyl butoxide, but only as prophylactic.