Browse Prescribing Notes by Therapeutic Subcategory

Pyrethrins
Pyrethrins are natural extracts of the chrysanthemum plant which effectively kill crawling lice but not unhatched nits. Pyrethrins are combined with piperonyl butoxide, which is a petroleum derivative that acts as a synergizing agent. Because the combination is not completely ovicidal, these products must be reapplied after 7–10 days to kill any newly hatched lice and prevent reinfestation.
Permethrin
Permethrin is a synthetic pyrethroid pesticide. Allergic reactions may occur in patients who are allergic to chrysanthemums. Permethrin has ovicidal activity in addition to lice killing activity. Treatment may be repeated if necessary.
Malathion
Malathion is a pediculicide and ovicide. The product, available for use on humans (eg, Ovide), is made of pharmaceutical grade malathion and is indicated for the treatment of head lice and their ova.
Lindane
Lindane is a cyclodiene pesticide that has lice killing activity, but it is not an effective ovicide. It is the most toxic pediculicide available, and its use should be reserved for resistant cases or in patients who cannnot use less toxic treatments. Human toxicity can be severe; extreme caution must be exercised when using this product.
Egg Removers or looseners
Lice egg removers or nit loosening gels are designed to be used with lice killing products. They act by loosening the cement by which lice eggs are attached to the hair shaft.

Tips for treating head lice infestations:
Apply and remove these products exactly as directed by the manufacturer. Do not use extra amounts of product.
Do not mix or use more than one type of medication concomitantly.
All of patient's clothing should be removed before treatment; clean clothing should be worn after treatment.
Nit combs should be used with all products to remove dead and remaining live lice after treatment. Inspection and combing should be repeated every 2–3 days. Determine need for re-treatment after 7–10 days based the product's recommended use.
Check for lice and nits for 2–3 weeks until eradication is complete.
Retreat with the same medication as directed except lindane, which must not be reapplied.

Tips for treating the household:
Machine wash all washable clothing and bed linens with which the infected person has come into contact during the two days before treatment. Hot water cycle (>130 F) should be used to wash clothes. Laundry should be dried using the hot cycle for at least 20 minutes.
Dry-clean clothes that are not washable or store in a plastic bag and seal for 2 weeks.
Soak combs and brushes for 1 hour in rubbing alcohol or other appropriate disinfectant, or wash with soap and hot water (>130 F).
Vacuum the floor and furniture. Fumigant sprays are not recommended.