Malathion lotion

Malathion is an organophosphate cholinesterase inhibitor that is hydrolyzed and inactivated by plasma carboxylesterases much faster in humans than in insects, thereby providing a therapeutic advantage in treating pediculosis (see Chapter 7). Malathion is available as a 0.5% lotion (Ovide) that should be applied to the hair when dry 4-6 hours later, the hair is combed to remove nits and lice. 

Malathion is available as aqueous and alcoholic lotions and a shampoo. 

Malathion shampoo is much less effective than lotions and not recommended. 

Mites are usually killed within minutes of application of malathion preparations, but the aqueous lotion should be left on for 24 hours and the alcoholic lotion for 12 hours, to ensure complete eradication. 

The lotion contains 0.005 g of malathion per milliliter in a vehicle of isopropyl alcohol (78%), terpineol, dipentene, and pine needle oil. The chemical name of malathion is... 

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