Clinical treatment of head lice | Lice

by Curavital | Dec 6, 2025 | Healthcare, Parkinsonism

Treatment options

Over the counter medicine

Many head lice medicines are available over the counter. Each over-the-counter product approved by the FDA for the treatment of head lice contains one of the following active ingredients.

Pyrethrins combined with piperonyl butoxide

Branded products* include A–200, Pronto, R&C, Rid and Triple X.

Pyrethrins are naturally occurring pyrethroid extracts from the chrysanthemum flower. Pyrethrins can only kill live lice, not unhatched eggs (nits). Treat a second time 9 – 10 days after the first treatment to kill any newly hatched lice before they can produce new eggs. Avoid use in people allergic to chrysanthemum or ragweed.

Pyrethrin is approved for use on children two years and older. The the effectiveness of pyrethrins may be reduced due to the development of resistance, but the incidence of resistance has not been well studied and is unknown.

Permethrin lotion, 1%

Brand name* product: Nix.

Permethrin is a synthetic pyrethroid similar to naturally occurring pyrethrins. Permethrin kills live lice, but not unhatched eggs. Permethrin can kill newly hatched lice for several days after treatment. You may need to treat again on day nine to kill any newly hatched lice before they can produce new eggs.

Permethrin is approved for use on children two months and older. Lice have developed some resistance to 1% permethrin, but the prevalence of resistance is unknown.

Prescription medicine

The following prescription drugs, in alphabetical order, are approved by the FDA for the treatment of head lice. If crawling lice are still present after a full course of treatment and retreatment, consider an alternative medication.

Benzyl alcohol lotion, 5%

Brand name* product: Ulesfia lotion.

Benzyl alcohol is an aromatic alcohol. It kills lice but does not kill eggs. Treat again after 7 days to kill any newly hatched lice before they can produce new eggs. Benzyl alcohol lotion is intended for use on people six months of age and older. Its safety in people over 60 is unknown. It can irritate the skin.

Ivermectin lotion, 0.5%

Brand name* product: Sklice.

Ivermectin lotion, 0.5% is approved for people six months of age and older. It kills lice, and although it does not kill eggs, it appears to prevent nymphs (newly hatched lice) from surviving. It is effective in most patients when given as a single application to dry hair without combing. It should not be used for retreatment without talking to a healthcare provider. Although not FDA-approved for the treatment of lice, ivermectin tablets given as a single oral dose of 200 micrograms/kg or 400 micrograms/kg repeated in 9-10 days are also effective against head lice. Do not use ivermectin tablets for children weighing less than 15 kg or for pregnant women.

Malathion lotion, 0.5%

Brand name* product: Ovide.

Malathion is an organophosphate. Malathion is pediculicidal (kills live lice) and partially ovicidal (kills some lice eggs). A second treatment is recommended if live lice are still present 7 – 9 days after the treatment. Malathion is intended for use in persons six years of age and older. Malathion can irritate the skin and is flammable. Avoid smoking or using electric heat sources, including hair dryers, curling irons, and curling or flat irons, when applying malathion lotion and while hair is wet.

Spinosad 0.9% topical suspension

Brand name* product: Natroba.

Spinosad is derived from soil bacteria. Since it kills live lice as well as unhatched eggs, retreatment is usually not necessary. Rivet combing is not required. Spinosad topical suspension is approved for the treatment of children six months and older. Repeat the treatment only if live (crawling) lice are seen seven days after the first treatment.

Second line treatment

Lindane is effective in treating head lice, but is no longer available in the United States or Canada because of its risk of serious side effects. It should only be used in affected individuals who have failed or are intolerant of first-line medications.

Lindane shampoo 1%

Lindane is an organochloride. The American Academy of Pediatrics (AAP) no longer recommends it as a pediculicide. Overuse, abuse or accidental ingestion of lindane can be toxic to the brain and other parts of the nervous system. Avoid withdrawal.

Do not use lindane to treat: