What is permethrin?

Permethrin is a pediculicide available in over-the-counter (OTC) medicines that kill head lice and their eggs (nits) and prevent re-infestation for up to 14 days. Permethrin can be found in single-ingredient head lice treatments.

What is permethrin used to treat?

  • Head lice
  • Nits

Common brands containing permethrin:

  • Nix
  • Store Brands (ex. Walmart’s “Equate” store brand or CVS Health store brand)

Safety guide for permethrin

Permethrin is approved by the U.S. Food and Drug Administration (FDA) and is safe and effective when used according to the Drug Facts label directions. To ensure proper use, read the consumer information insert enclosed with the product. These medicines are for external use only.

Safe Use Tips:

  • You should not use a hair conditioner prior to application.
  • You do not need to shampoo your hair prior to using a product in spray form.
  • During application, do not use near your eyes. Keep your eyes closed tightly and protect them with a washcloth or towel. If any medicine gets into your eyes, immediately flush with large amounts of water.
  • A special fine-tooth comb is provided with the product to help with lice and nit removal. See the consumer information insert for appropriate use.
  • If live lice are seen seven or more days after the first treatment, a second treatment should be given.

Ask a Healthcare Provider Before Use If:

  • You are allergic to ragweed. Breathing difficulty or an asthmatic episode may occur.
  • You are pregnant or breastfeeding.
  • You have lice in the eyebrows or eyelashes.

Do Not Use If:

  • Do not use inside the nose, ear, mouth, or vagina.

Stop Use and Ask a Doctor If:

  • You have difficulty breathing.
  • Eye irritation occurs.
  • Skin or scalp irritation continues or infection occurs.
  • You accidentally swallow the medicine. Immediately contact a healthcare provider or the poison control national helpline at 800.222.1222.

What are the side effects of permethrin?

  • Scalp itching or redness may occur.