Permethrin

Increased risk of local skin irritation, burning, stinging, or itching

Apply permethrin first, then corticosteroids if needed, allowing adequate time between applications. Monitor for increased skin irritation.

Potential for minor alterations in permethrin metabolism or metabolism of co-administered drugs, but clinically significant effects are highly unlikely due to low systemic absorption of permethrin.

Generally no specific management required due to low systemic absorption of permethrin. Monitor for unexpected effects if co-administered with drugs with narrow therapeutic indices that are sensitive substrates of these enzymes, though this is largely theoretical.

May reduce efficacy of permethrin if applied immediately before, or increase skin irritation if applied concurrently with other irritants.

Apply permethrin to clean, dry skin. Avoid applying other topical agents immediately before or after permethrin. Allow permethrin to remain on skin for the recommended duration before washing off or applying other products.