There are several pediculicides on the market, both over-the-counter and prescription. Some concern has been raised about head lice having grown resistant to some of the more common treatments, but they are usually effective. In fact, Frankowski believes a lot of times people may think the lice are resistant when in fact they didn't use the products correctly (you typically need to follow up the treatments with thorough nit combing and repeat the whole process in 7 to 10 days to get any live eggs that may have been left behind and hatched since the first treatment). No matter where they stand on using chemicals to kill lice, experts agree that it is imperative that you follow the medication directions exactly. Just as you wouldn’t double up your daughter’s antibiotic dose, don’t overdo it with a medication simply because you use it like shampoo.

Permethrin or Pyrethrin: Available over the counter and sold under brand names like Nix(permethrin) and  Rid(pyrethrin), these pesticides are considered the first-line medical treatment for lice. “They are the safest and most cost-effective,” says Dr. Frankowski. “If applied exactly as recommended with a second treatment 7-10 days later, it should result in very high rate of elimination of the infestation,” says Dr. Bocchini. “If that doesn’t seem to work, the best thing to do is to see your physician for a second confirmation of the diagnosis and a prescription-based treatment.” A key to treatment with these products, however, is also following up each application with a thorough going over with the accompanying nit comb.

For stubborn cases:

Ulesfia: A newly-approved prescription treatment for lice, this benzyl alcohol lotion suffocates lice, though with better success than home treatments, equal to other pesticides according to a recent study. It is expensive and not all insurance plans cover it. If you use it, Dr. Frankowski says to be careful to keep it out of the eyes, as it can cause irritation. Side effects can include headache and stomach upset. A nit comb should be used after treatment.

The two products that follow come with important caveats:

Malathion: Also available by prescription, malathion, which is also used to control mosquitoes, works by killing the eggs and lice. The main precaution with malathion is that it is flammable and should not be used near any products that can emit sparks, such as cigarettes or hair dryers.

Lindane: Experts recommend steering clear of this prescription medication, a neurotoxin which has been banned in most countries and in California, but is still available in other states. “Most physicians will no longer prescribe lindane,” says Dr. Frankowski. “It’s been around so long there is a lot of resistance to it, and it can get absorbed by the skin if not used properly and cause seizures.”

The bottom line for all of these medications is to remember that they are pesticides, so it’s critical to:

• Make sure you have a correct diagnosis
• Consult your physician
• Use them exactly as directed. If it says to wear gloves, avoid the eyes or only keep on the scalp for a certain amount of time, do it!
• Keep them safely out of reach of children since ingesting them can have serious medical consequences.