Overview
Permethrin 5% cream is a topical scabicide used to treat Sarcoptes scabiei infestations. It works by disrupting sodium channel function in parasites, leading to paralysis and death. A single application is typically curative for most patients.
Mechanism of Action
Permethrin is a synthetic pyrethroid that acts on parasite nerve cell membranes by prolonging sodium channel activation. This disrupts neuronal function, causing paralysis and death of the scabies mite.
Indications
- Treatment of scabies infestation caused by Sarcoptes scabiei
Common Doses
- 5% cream (30g tube for average adult)
Dosage
Apply cream thoroughly from head to soles of feet, using approximately 30g for average adult. Leave on for 8-14 hours before washing off. Infants require application to scalp, temple, and forehead. One application is generally curative.
Contraindications
- Hypersensitivity to permethrin, any cream component, or other synthetic pyrethroids/pyrethrins
Side Effects
- Burning/stinging (10% of patients)
- Pruritus (7%)
- Erythema, numbness, tingling, rash (1-2%)
- Headache, fever, dizziness, GI symptoms (rare)
- Seizures (extremely rare, not medically confirmed)
Interactions
- No significant drug interactions documented for topical use
Counseling Points
- Apply to clean, dry skin from neck down (including soles)
- Leave on for 8-14 hours before showering
- Wash bedding and clothing in hot water
- Treat all household contacts simultaneously
- Persistent itching for 2-4 weeks is common and doesn't mean treatment failed
- Retreat only if live mites are visible after 14 days