permethrin: clinical use

Prescribing considerations

• Confirm the likely infestation and distinguish persistent post-scabies itch from ongoing infestation or reinfestation.
• Coordinate scabies management for household and other close contacts to reduce transmission.
• Children aged 2 to 23 months require close medical supervision.
• Seek specialist input for suspected crusted scabies, very young infants or difficult outbreaks.
• Warn about eye and mucosal exposure, environmental aquatic toxicity and fabric fire risk.

Contraindications and cautions

• Hypersensitivity to permethrin, pyrethrins or any product excipient.
• Chrysanthemum or other compositae hypersensitivity requires careful assessment and use only when strictly indicated.

Monitoring

• Monitor clinically for allergic or irritant reactions.
• Assess for new burrows or lesions, application errors, untreated contacts and secondary bacterial infection if symptoms persist.
• No routine laboratory monitoring is specified for topical treatment.

Clinical pharmacology

Permethrin is a synthetic pyrethroid ectoparasiticide. Percutaneous absorption is very low; absorbed medicine is rapidly hydrolysed and metabolites are excreted mainly in urine.

Formulation and product differences

• The selected product is a white to off-white vanishing cream for cutaneous use.
• Product excipients may cause contact dermatitis or delayed allergy and may impair latex barrier products.
• The container contains latex rubber, and treated fabrics can ignite more readily.

Cream

Route: Cutaneous

Strengths: 5% w/w