Permethrin for lice

Examples

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Permethrin is available in both nonprescription and prescription strengths.

Brand Name	Generic Name
Nix	permethrin 1%

Brand Name	Generic Name
Elimite	permethrin 5%

Permethrin 1% (Nix) is a nonprescription creme rinse used to treat head lice. Instructions for use:

• Wash and towel dry the hair.
• Apply enough of the creme rinse to the hair to saturate the hair and scalp.
• Leave the creme rinse on for 10 minutes.
• Rinse the creme rinse off with water.
• Avoid getting permethrin in the eyes. Although the product is not known to be harmful to the eyes, rinse the eyes well with water if the creme rinse gets into them.
• Experts do not agree whether it is necessary to comb the nits out of the hair after treatment with Nix. You may wish to do so for cosmetic reasons.

When permethrin is used to treat pubic lice, a second treatment is recommended in 7 to 10 days. Most experts advise a second treatment 7 to 10 days after the first treatment for head lice.¹

Permethrin 5% (Acticin or Elimite) is a prescription cream that is applied to the skin or hair, left on for 8 to 14 hours, and then rinsed off.

How It Works

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Permethrin kills lice and their eggs (nits). Permethrin continues to kill lice and eggs for at least 2 weeks after it has been rinsed off.

Why It Is Used

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Nonprescription permethrin creme rinse (Nix) is a common first choice for treating head lice.

Prescription permethrin 5% (Acticin or Elimite) may be used to treat cases of lice that persist after treatment with other nonprescription products.

How Well It Works

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Permethrin is very safe and effective. But resistance to permethrin has been reported in many countries (such as United Kingdom and United States).^{1 2} If resistance to permethrin is noted, your health professional can recommend other treatment (such as malathion or pyrethrin) or a combination of treatments, such as permethrin cream along with trimethoprim sulfamethoxazole (Bactrim, Septra).

Side Effects

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Permethrin is very safe and has few side effects. Itching, burning or stinging, or temporary redness of the skin may occur. If these side effects persist, call your health professional.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

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Nonprescription permethrin is easy to use, safe, and usually effective.

Overuse of lice medications (such as reapplying the creme rinse or cream when only a single use is prescribed) can irritate the skin and may increase the risk of side effects from some products. It is common for itching to persist for 7 to 10 days after treatment. Itching is not a reason to treat the person again.

Complete the new medication information form (PDF) (What is a PDF document?) to help you understand this medication.

References

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Citations

1. American Academy of Pediatrics (2006). Pediculosis capitis (head lice), pediculosis corporis (body lice), pediculosis pubis (pubic lice). In LK Pickering, ed., Red Book: 2006 Report of the Committee on Infectious Diseases, 27th ed., pp. 488–493. Elk Grove Village, IL: American Academy of Pediatrics.

2. Chosidow O (2000). Scabies and pediculosis. Lancet, 355: 819–826.

Credits

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Author	Debby Golonka, MPH
Author	Ralph Poore
Editor	Susan Van Houten, RN, BSN, MBA
Associate Editor	Marianne Flagg
Associate Editor	Pat Truman, MATC
Primary Medical Reviewer	Kathleen Romito, MD - Family Medicine
Primary Medical Reviewer	Michael J. Sexton, MD - Pediatrics
Specialist Medical Reviewer	Thomas Emmett Francoeur, MDCM, CSPQ, FRCPC - Pediatrics
Last Updated	November 24, 2006