The 5 % permethrin cream is not licensed for infants younger than two months. For this age group, alternative treatments should be discussed with a healthcare professional.
Rinse the eyes immediately with plenty of water or saline for several minutes. Seek medical attention promptly, even if irritation subsides.
Permethrin is classified as category B3 in the UK, indicating limited human data but no evidence of risk in animal studies at therapeutic doses. Use only if the potential benefit outweighs any possible risk, and after consulting a healthcare provider.
Once opened, the tube should be used within 6 months if stored as instructed. Discard any product that changes in color, texture, or odor.
Avoid applying the cream to open wounds, severe eczema, or heavily inflamed skin, as absorption may increase and irritation may worsen.
Resistance has been reported in some regions, especially with repeated over-the-counter use. If treatment fails, a pharmacist may recommend an alternative agent such as malathion or a different class of pediculicide.
Yes. Wash all clothing, bed linens, and towels used during the infestation in hot water (≥ 60 °C) and dry on a high heat setting. Items that cannot be washed should be sealed in a plastic bag for at least 72 hours.
Permethrin formulations for human use are not intended for animals. Some veterinary products contain permethrin, but they have different concentrations and should only be used as directed by a veterinarian.
The 5 % cream is formulated for the treatment of scabies and is applied to the entire body, whereas the 1 % shampoo is designed for head-lice control, applied to the hair and scalp only. Both contain permethrin but differ in concentration and intended site of use.
Hair loss is not a recognized side effect of permethrin shampoo. Temporary scalp irritation may occur, but it does not lead to permanent hair loss.
Permethrin is a synthetic pyrethroid used as a topical antiparasitic agent. In the United Kingdom it is available in a 30 g tube as a cream (commonly 5 % strength) for the treatment of scabies, and as a 1 % shampoo for head-lice infestation. The medication is classified under Skin Care, Antiparasitics and is supplied by prescription (POM) for scabies, while the lice preparation may be purchased over the counter. Permethrin works by disrupting the nervous system of mites and lice, leading to paralysis and death of the parasite.
Permethrin belongs to the pyrethroid class of insecticides. It binds to voltage-gated sodium channels on the nerve membranes of arthropods, prolonging their opening and causing repetitive nerve firing. The resulting hyperexcitation leads to paralysis and eventual death of the parasite. Because human skin limits systemic absorption, the drug acts locally with minimal exposure to the central nervous system. The onset of action is rapid-parasites are usually killed within a few hours of application-while the clinical effect (relief of itching or eradication of lice) may take 1-2 days as the skin heals.
Both indications are approved by the UK Medicines and Healthcare products Regulatory Agency (MHRA) and supported by NICE guidance for the management of scabies and lice.
If uncertainty exists regarding a patient’s suitability, a pharmacist or prescriber should be consulted before initiating therapy.
Topical permethrin has minimal systemic absorption, so clinically significant drug-drug interactions are rare. Nonetheless:
Patients should inform their healthcare provider of all medicines, supplements, and herbal products they are using.
Scabies (5 % cream, 30 g tube)
Apply a thin layer over the entire body from the neck down, including the soles of the feet, and in children, the scalp and face (excluding eyes and mouth).
Leave the cream on for 8-14 hours (typically overnight).
Wash off thoroughly with warm water and gentle soap.
A single treatment is usually sufficient; a repeat dose after 7 days is recommended if itching persists, indicating possible reinfestation.
Head Lice (1 % shampoo)
Apply to dry hair, ensuring thorough coverage of the scalp and hair shafts.
Leave in place for 10 minutes before rinsing with warm water.
Comb out dead nits with a fine-toothed lice comb.
A second application after 7-10 days may be required to eliminate newly hatched lice.
Missed Dose - If a treatment is forgotten, apply the full dose as soon as possible; do not double the dose.
Overdose - Systemic overdose is unlikely. In the event of extensive skin exposure or accidental ingestion, seek medical attention; supportive care is the mainstay of treatment.
Discontinuation - Treatment is usually completed after one or two applications as directed. No tapering is needed.
This article provides educational information about permethrin and is not a substitute for professional medical advice. Treatment decisions, including use for unapproved indications, must be made under the guidance of a qualified healthcare provider. The content is intended for informational purposes and does not constitute medical recommendations. Always consult a physician before starting, stopping, or changing any medication regimen.
