Phenothrin
Phenothrin is a synthetic pyrethroid insecticide used primarily as a topical treatment for ectoparasitic infestations, most notably head lice and pubic lice. It works by disrupting the nervous system of insects and arthropods, causing paralysis and death. This medication is typically applied to the scalp or affected areas as a shampoo or lotion preparation.
A topical insecticide used to treat lice infestations by paralyzing and killing ectoparasites.
Key facts at a glance
- ATC
- P03AC03
- RxNorm
- 33303
- Generic
- Phenothrin
- Class
- atc-p03
- Brands
- —
- Availability
- rx
- Lactation
- unknown
- Routes
- topical
- Forms
- —
- Regions
- US, EU, CN, JP
- Monitoring
- —
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Treatment of pediculosis (head lice, body lice, and pubic/crab lice infestations). May also be used against other ectoparasites such as fleas and some mites.
As a synthetic pyrethroid, phenothrin acts on the nervous system of insects by affecting sodium channels in nerve cell membranes, causing prolonged depolarization. This leads to hyperexcitability, paralysis, and eventual death of the parasite.
For external use only. Avoid contact with eyes, nose, and mouth. Should not be used on infants or individuals with known pyrethroid hypersensitivity. Resistance to pyrethroids has been reported in some lice populations. Treatment typically involves application to dry hair/scalp, followed by rinsing after a specified time. A second treatment may be recommended after 7-10 days to eliminate newly hatched lice.
Official drug label
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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 29, 2026. · Read our editorial policy