Health Library: ABCDEFGHIJKLMNOPQRSTUVWXYZ

Permethrin Topical lotion

What is this medicine?

PERMETHRIN (per METH rin) is used to treat head lice infestations. It acts by destroying both the lice and their eggs.

How should I use this medicine?

This medicine is for external use only. Do not take by mouth. Shampoo your hair with regular shampoo, rinse and towel dry. Do NOT use a shampoo with a conditioner. Shake well before applying. Apply enough medicine to your hair to wet the hair and scalp (usually about 2 tablespoons), and thoroughly rub the medicine into your hair and scalp. Make sure you get behind the ears and on the back of the neck. Keep this medicine away from your eyes. If you accidentally get some in your eyes, rinse your eyes with water right away. Leave on your hair for 10 minutes, unless directed otherwise by your doctor or health care professional. Then, rinse thoroughly with water. Dry with a clean towel. When your hair is dry, comb it with a fine toothed comb to remove any leftover nits (eggs) or nit shells. If you still have lice after one week, see your doctor or health care professional. You may need a second treatment. If you are applying this medicine to another person, wear plastic or disposable gloves to protect yourself from infestation.

Talk to your pediatrician regarding the use of this medicine in children. While this drug may be prescribed for children as young as 2 months old for selected conditions, precautions do apply.

What side effects may I notice from receiving this medicine?

Side effects that usually do not require medical attention (report to your doctor or health care professional if they continue or are bothersome):

  • itching

  • redness or mild swelling of the scalp

  • stinging or burning

  • tingling sensation

What may interact with this medicine?

Interactions are not expected. Do not use any other skin products on the affected area without telling your doctor or health care professional.

What if I miss a dose?

This does not apply.

Where should I keep my medicine?

Keep out of the reach of children.

Store at room temperature away from heat and direct light. Do not refrigerate or freeze. After treatment, throw away any unused medicine.

What should I tell my health care provider before I take this medicine?

They need to know if you have any of these conditions:

  • asthma

  • an unusual or allergic reaction to permethrin, veterinary or household insecticides, other medicines, chrysanthemums, foods, dyes, or preservatives

  • pregnant or trying to get pregnant

  • breast-feeding

What should I watch for while using this medicine?

This medicine is used as a single application treatment. If live lice are observed 7 or more days after initial application, a second treatment may be needed.

Head lice can be spread from one person to another by direct contact with clothing, hats, scarves, bedding, towels, washcloths, hairbrushes, and combs. All members of your household should be examined for head lice and should receive treatment if they are found to be infected. If you have any questions about this, check with your doctor or health care professional.

To prevent reinfection or spreading of the infection, the following steps should be taken: Machine wash all clothing, bedding, towels, and washcloths in very hot water and dry them using the hot cycle of a dryer for at least 20 minutes. Clothing or bedding that cannot be washed should be dry cleaned or sealed in an airtight plastic bag for 2 weeks. Shampoo any wigs or hairpieces. You should also wash all hairbrushes and combs in very hot soapy water (above 130 degrees F) for 5 to 10 minutes. Do not share your hairbrushes or combs with other people. Wash all toys in very hot water (above 130 degrees F) for 5 to 10 minutes or seal in an airtight plastic bag for 2 weeks. Also, clean the house or room by vacuuming furniture, rugs, and floors.