Treatment	Ovicidal?	Mechanism of action	Directions (per package inserts)	Effectiveness	Cost*	Comments
Benzyl alcohol 5% lotion (Ulesfia); prescription	No	Suffocation	Apply to dry hair, leave on for 10 minutes then rinse; repeat in seven days	75% to 76% of patients are lice free at 14 days11	— ($450) for two bottles	Can be costly for long hair (dosing is based on hair length) Must be used in conjunction with a lice comb (also called nit comb) Approved for persons six months and older, may be used in pregnant and lactating women
Dimethicone solution (Nix Ultra, Lice MD); OTC	No	Suffocation	Spray all over dry hair, and massage until wet; let it sit for 30 minutes, then comb into hair; leave on overnight; wash out, and use a lice comb; repeat in eight to 10 days	70% to 96% of patients are lice free at 14 days (study of dimethicone 100%)12,13	— ($10 to $20) for one bottle	May cause eye irritation Should not be used in children younger than two years
Isopropyl myristate (Resultz); OTC†	No	Exoskeleton dissolution	Apply to dry hair and scalp, leave on for 10 minutes then rinse with warm water; repeat in eight to 10 days	54% to 82% of patients are lice free at 14 to 21 days12	—	May cause local and eye irritation Not recommended for children younger than four years
Ivermectin 0.5% lotion (Sklice); prescription	Not directly, but lice hatched from treated eggs die within 48 hours	Neurotoxic to lice4	Apply to dry hair and scalp, leave on for 10 minutes then rinse; one application is sufficient	74% of patients are lice free at 15 days14	— ($360) for one tube	Rare adverse effects include skin and eye irritation, erythema, burning, dryness
Ivermectin, oral (Stromectol); prescription‡	Partial	Neurotoxic to lice	200 mcg per kg, two doses seven to 10 days apart8	92% to 97% of patients are lice free at 14 to 15 days after two doses15	$5 ($8) for one 3-mg tablet (dosing varies based on weight)	Do not use in children weighing less than 33 lb (15 kg) or in pregnant women
Malathion 0.5% lotion (Ovide); prescription	Partial	Neurotoxic to lice	Apply to dry hair until hair and scalp are wet, allow to dry naturally, shampoo eight to 12 hours later, rinse and use a lice comb; repeat after seven to nine days only if live lice are still present	80% of patients are lice free at 14 days16	$150 ($270) for one bottle	Flammable; do not use with a hair dryer or near cigarettes or an open flame
Permethrin 1% shampoo (Nix); OTC	No	Neurotoxic to lice	Apply to damp hair, leave on for 10 minutes then rinse; repeat in seven days	50% to 97% of patients are lice free at 14 days1,8,17	$20 for two treatments	First-line treatment1
Pyrethrins 0.3%/piperonyl butoxide 4% shampoo or mousse (Rid); OTC	No	Neurotoxic to lice	Apply to dry hair, leave on for 10 minutes then rinse; repeat in seven days	62% to 94% of patients are lice free (unclear time frame)1	— ($15 to $20) for two treatments	Piperonyl butoxide is thought to prolong the activity of pyrethrins Avoid in patients with chrysanthemum allergy
Spinosad 0.9% suspension (Natroba); prescription	Yes	Neurotoxic to lice	Apply to dry hair, leave on for 10 minutes then rinse; repeat in seven days only if live lice are present	68% to 87% of patients are lice free at 14 days16	$200 ($280) for one bottle	May be used without a lice comb, although use of a lice comb improves results Safe for use in children four years and older Do not use in infants younger than six months because it contains benzyl alcohol