Key points
- Both over-the-counter and prescription medications are available to effectively treat head lice.
- If the medication you use does not kill nits (lice eggs), then retreatment is recommended.
Treatment options
Over-the-counter medications
Many head lice medications 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
Brand name* 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 for people allergic to chrysanthemums or ragweed.
Pyrethrin is approved for use on children two years of age and older. The efficacy of pyrethrins may be reduced because of development of resistance, but the prevalence 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 of age and older. Lice have developed some resistance to 1% permethrin, but prevalence of resistance is unknown.
Prescription medications
The following prescription medications, in alphabetical order, are approved by the FDA for head lice treatment. 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 persons who are six months of age and older. Its safety for people over 60 years is unknown. It can irritate 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, appears to prevent nymphs (newly hatched lice) from surviving. It is effective in most patients when given as a single application on dry hair without nit 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 in 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 tables for children weighing less than 15 kg or in pregnant people.
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 still are present 7 – 9 days after treatment. Malathion is intended for use on persons six years of age and older. Malathion can irritate skin and is flammable. Do not smoke or use electrical heat sources, including hair dryers, curlers, and curling or flat irons, when applying malathion lotion and while the 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 needed. Nit combing is not required. Spinosad topical suspension is approved for the treatment of children six months of age and older. Repeat treatment only if live (crawling) lice are seen seven days after the first treatment.
Second-line treatment
Lindane is effective at treating lice but is no longer available in the United States or Canada due to its risk for severe side effects. It should be used only in infested people who have failed or do not tolerate first line medications.
Lindane shampoo 1%
Lindane is an organochloride. The American Academy of Pediatrics (AAP) no longer recommends it as a pediculicide. Overuse, misuse, or accidentally swallowing lindane can be toxic to the brain and other parts of the nervous system. Avoid retreatment.
Do not use lindane to treat:
- Premature infants or children
- Elderly people
- People with HIV
- People with seizure disorders
- People who are pregnant or breast-feeding
- People with irritated skin or sores in the infested area
- People who weigh less than 110 pounds
Treatment precautions
- Do not use extra amounts of any lice medication unless instructed to do so by your physician and pharmacist. The drugs used to treat lice are insecticides and can be dangerous if misused or overused.
- Keep all the medications listed above out of your eyes. If they get into your eyes, flush them immediately.
- Do not treat a person infested with lice more than 2 – 3 times with the same medication if it isn't successful. Incorrect use or resistance to medicine can reduce effectiveness.
- Do not use different head lice drugs at the same time unless instructed to do so by your healthcare provider or pharmacist.
- The AAP recommends rinsing all topical pediculicides from the hair over a sink, rather than in the shower or bath to limit skin exposure. The AAP also recommends warm water rather than hot water to minimize absorption.
*Use of trade names is for identification purposes only and does not imply endorsement by CDC, the Public Health Service, or by the U.S. Department of Health and Human Services.