permethrin at a glance
Medicine class
Topical synthetic pyrethroid ectoparasiticide
Licensed uses
Scabies; crab lice in adults
Application
For external use on clean, dry, cool skin; avoid eyes, mucous membranes and open wounds
Fire safety
Keep treated skin, clothing and bedding away from smoking and naked flames
What is permethrin used for?
The selected UK product is licensed for:
Scabies in adults and children aged 2 months and over
Crab lice in adults
How does permethrin work?
Permethrin disrupts electrical activity across nerve-cell membranes in mites and lice. This causes overactivity, loss of coordination and death of the parasite.
permethrin preparations and strengths
Cream
Route: Cutaneous
Strengths: 5% w/w
How to take permethrin
Use only on the skin and follow the product leaflet or clinician’s instructions for the areas requiring coverage.
Apply to clean, dry and cool skin, rather than immediately after a warm bath.
Cover all areas specified in the product instructions, including easily missed areas.
Avoid the eyes, mouth, inside the nose, mucous membranes and open wounds. Rinse promptly with plenty of water if it enters an eye.
Do not apply the cream to eyelashes.
Wash treated skin after the contact time stated in the product instructions.
Use clean clothing and bedding and follow household-control advice for scabies.
Keep treated fabrics away from cigarettes, flames and other ignition sources.
permethrin side effects
Common or expected effects
- Itching
- Skin redness or rash
- Tingling, stinging or burning sensations
- Dry skin
Get urgent medical advice
- Breathing difficulty in a sensitive or allergic person
- Severe hypersensitivity or a widespread allergic skin reaction
permethrin in pregnancy
Scabies treatments including permethrin can be used in pregnancy and are not known to harm the unborn baby, although human data are limited. The selected product information advises use only when clearly needed, so discuss treatment with a GP, midwife or pharmacist.
permethrin while breastfeeding
Only very small amounts are expected to enter the bloodstream after topical use, making clinically important transfer into milk unlikely. Specialist advice supports permethrin for pubic lice during breastfeeding, but the selected product information advises considering whether treatment or breastfeeding should be temporarily interrupted; seek individual advice, especially for a premature or unwell infant.
permethrin interactions
No conventional medicine interactions are known, but these practical issues matter.
Topical corticosteroids
Using them for eczema-like symptoms before scabies treatment may suppress the local immune response and worsen the infestation; review treatment sequencing with a clinician.
Latex condoms and diaphragms
Paraffin-containing cream ingredients may reduce the reliability of latex barrier contraception used at the same time.
Common questions about permethrin
Answers are fully visible for fast scanning and source review.
What is permethrin cream used for?
The selected cream is licensed for scabies in adults and children from 2 months and for crab lice in adults.
What should I do if permethrin gets in my eyes?
Rinse immediately with plenty of water or saline. Seek advice if significant irritation continues.
Does itching after permethrin mean scabies treatment failed?
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.