[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Scabicides and pediculicides](https://durgical.com/en/pharmacology/classes/scabicides-and-pediculicides/) › Permethrin # Permethrin ## Scabicides and pediculicides? Scabicides and pediculicides A synthetic pyrethroid cream that paralyses the scabies mite. First-line topical treatment for scabies; also used for lice, where resistance is common. Updated Nov 1, 2026 ## Quick facts **Group** [Scabicides and pediculicides](https://durgical.com/en/pharmacology/classes/scabicides-and-pediculicides/) **Target** Voltage-gated sodium channel in the nerve membrane of the mite or louse **Used for** Scabies · Head **Key effects** Mild · Itching · Rash **Monitor** Signs of secondary bacterial infection **ATC** P03AC04 No doses: the clinician sets them by the current guideline. On this page - The basics Mechanism of action - Indications - Adverse effects - Pharmacokinetics - Memory aid - Safety Contraindications - Key interactions - What is monitored - Administration and safety - Pregnancy and breastfeeding - Nursing care - Study Test yourself - Connections Connections ## Mechanism of action Permethrin is a synthetic pyrethroid, related to the natural pyrethrins. It acts on the nerve cell membrane of mites, lice and other arthropods and disturbs the sodium current that controls repolarisation: the channels stay open, repolarisation is delayed, and the parasite is paralysed and dies. Very little crosses human skin, and what is absorbed is quickly split by ester hydrolysis into inactive metabolites. - Permethrin reaches the nerve membrane of the mite or louse - Sodium channels stay open; repolarisation is delayed - The parasite is paralysed and dies - The little absorbed in people is hydrolysed to inactive metabolites ## Indications - Scabies (Sarcoptes scabiei), including in pregnancy and in infants from two months [Scabies →](https://durgical.com/en/conditions/scabies/) - Head, body and pubic lice (lotion), where local resistance allows [Pediculosis (head, body and pubic lice) →](https://durgical.com/en/conditions/pediculosis/) ## Adverse effects ### Common - Mild, transient burning or stinging after application - Itching, redness, numbness or tingling of the skin - Rash - Temporary worsening of the itch and redness of scabies ### Serious (rare, important) - Allergic reaction with difficulty breathing - Seizures, reported very rarely ## Contraindications - Hypersensitivity to permethrin, to any synthetic pyrethroid or pyrethrin, or to any component ## Key interactions **Hair conditioner or conditioning shampoo (head-lice lotion)** Coats the hair and makes the lotion work less well; plain shampoo is used before treatment. ## What is monitored - Live mites 14 days after treatment mean a second application is needed - Persistent itch alone is rarely treatment failure - Signs of secondary bacterial infection (pus, crusts, impetigo) - That all household members and close contacts were treated ## Administration and safety - Cream is massaged into all the skin from the neck to the soles, including skin folds, between fingers and toes and under the nails; in infants and older adults also the scalp, temples and forehead. - It is left on overnight and then washed off by bathing; it is reapplied to the hands if they are washed during that time. - Kept away from the eyes, mouth, nose and other mucous membranes; eyes are flushed with water if contaminated. - Head-lice lotion is applied to towel-dried hair, left on briefly and rinsed over a sink, not in the shower. ## Pregnancy and breastfeeding Very little is absorbed, and it is considered a safe choice for scabies in pregnancy and breastfeeding. ## Nursing care - Check that every household member and close contact is treated on the same day, even without symptoms. - Teach to wash clothing, towels and bedding hot, or seal unwashable items in a bag for several days. - Explain that itch may continue for weeks and is not, alone, a reason to re-treat. - Watch for crusted scabies in immunosuppressed patients: it is highly contagious, and their rooms need careful cleaning. ## Pharmacokinetics **Absorption** Very little crosses the skin, even in heavy scabies. **Metabolism** Rapid ester hydrolysis to inactive metabolites. **Elimination** Mainly in urine. **Onset and duration** Kills mites during the application; itch can persist for weeks after cure. ## Memory aid PERMEthrin: Paint Every Region from neck to soles, and Make Everyone in the house do it the same night. ## Test yourself Think of the answer, then tap the question to see it. ## How does permethrin kill the scabies mite? It disturbs the nerve sodium channels of the mite, delaying repolarisation, so the mite is paralysed and dies. ## Which body areas are often missed when applying permethrin for scabies? Between the fingers and toes, under the nails, skin folds, the waist and buttocks, and the soles; in infants and older adults also the scalp and face. ## Why is permethrin less useful for head lice in many countries? Resistance in lice (mutations in the sodium channel) has become common. [Add to my cards (3)](https://durgical.app/estudiar/?add=/en/pharmacology/permethrin/) [More Pharmacology questions →](https://durgical.com/en/practice/?f=pharmacology) ## Connections ## Related drugs 2 - [Benzyl benzoate](https://durgical.com/en/pharmacology/benzyl-benzoate/) - [Ivermectin](https://durgical.com/en/pharmacology/ivermectin/) ## Related conditions 2 - [Scabies](https://durgical.com/en/conditions/scabies/) - [Pediculosis (head, body and pubic lice)](https://durgical.com/en/conditions/pediculosis/) [← Back to the class: Scabicides and pediculicides](https://durgical.com/en/pharmacology/classes/scabicides-and-pediculicides/) Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given. Sources: [Permethrin Topical: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a698037.html) (MedlinePlus (U.S. National Library of Medicine), 2026); [DailyMed - PERMETHRIN cream](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=0c92aca1-0daa-4b24-9348-f9d42fec478a) (DailyMed (U.S. National Library of Medicine), 2026); [Scabies: Diagnosis and Treatment with Images](https://dermnetnz.org/topics/scabies) (DermNet, 2026); [eEML - Electronic Essential Medicines List](https://list.essentialmeds.org/?query=permethrin) (World Health Organization, 2025). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/pharmacology/permethrin/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/permethrin/