pyrethrins + piperonyl butoxide

RID is an over-the-counter (OTC) topical treatment for lice infestation (pediculosis), currently developed and marketed by Oystershell (following its acquisition of the brand from Prestige Consumer Healthcare in 2021). The primary formulation is a synergized pyrethrin shampoo or gel. It contains two main active ingredients: pyrethrins, which are natural insecticides derived from chrysanthemum flowers, and piperonyl butoxide, a synergist. The pyrethrins act as neurotoxins by targeting the voltage-gated sodium channels in the nervous system of lice, leading to prolonged channel opening, hyperexcitation, paralysis, and death. Piperonyl butoxide enhances this effect by inhibiting the cytochrome P450 enzymes (microsomal monooxygenases) within the lice that would otherwise detoxify the pyrethrins. It is indicated for the treatment of head lice, pubic (crab) lice, and body lice.

Brand names

RIDRID Max

Other names

synergized pyrethrinspyrethrins/piperonyl butoxide