In the February 2000 issue, Consumer Reports magazine
reconfirms lice resistance to permethrin, the active ingredient in Nix.
They also go on to say that they "..can't recommend Ovide, because
of the lack of information on safety for young children."
The article states that since the development of resistance to Nix and
other over-the-counter remedies, Ovide, a prescription-only remedy, was
relaunched after being discontinued in the early 1990's. Ovide's
active ingredient is malathion, a neurotoxic insecticide which can be absorbed
through the skin and mucous membranes. Consumer Reports continues...
"The malathion contained in a single Ovide treatment can be up to 30
times the recognized safe one-time dose for a young child."
Consumer Reports recommends that parents abandon any lice treatment that fails to kill the lice and nits,
emphasizing that "..further treatments will do no good." They
also reaffirm the recommendation they made in their February 1998 issue:
"The bottom line is to comb and comb and comb." says Dr. Susan
Aronson, "Mechanical removal is more
certain than chemical killing."
They conclude with a cautionary note regarding accurate
diagnosis of lice infestations. Parents and health
professionals have been known to confuse hair debris and other artifacts with
nits, resulting in unnecessary pesticide exposure -- a problem the NPA has
helped to prevent since it began in 1983.
since 1936: Test, Inform, Protect. We accept no ads.
Head lice update:
Scratch some remedies
February 2000 -
The battle against head lice has seen some developments, not entirely encouraging, since our February 1998 report. First, it's been confirmed that lice have become resistant to the relatively safe insecticide used in the most popular over-the-counter remedy. Second, a prescription-only treatment is again on the market--and actively promoted among pediatricians and school nurses--even though its safety for young children has never been established.
Researchers at the Harvard School of Public Health recently reported that head lice collected from children in Massachusetts and Idaho are no longer killed by permethrin, the active ingredient in Nix, the nation's best-selling lice shampoo. The researchers didn't test pyrethrum, the active ingredient in other over-the-counter lice shampoos, but it's likely that lice are growing resistant to it as well because it's so widely used.
Capitalizing on this development, a prescription-only lice remedy called Ovide was recently relaunched after having been discontinued in the early 1990s. Ovide's active ingredient is malathion, a neurotoxic insecticide that's readily absorbed through the skin and through mucous membranes.
The malathion contained in a single Ovide treatment can be up to 30 times the recognized safe one-time dose for a young child. Yet according to the product's label, no tests have been done to measure how much of the malathion is absorbed through the scalp, nor is it known whether Ovide is safe for children under 6.
Based on animal tests, the Food and Drug Administration estimates that skin absorption is low enough to make the product safe for older children, says Martin Okun of the agency's Division of Dermatology and Dental Drug Products. If more than 50,000 prescriptions a year are written for children 6 and under, the agency will consider asking the manufacturer to do additional tests, Okun said.
So where does this leave the families of the 10 million school-age kids who get lice each year? Consumer Reports agrees with Richard Pollack, lead researcher on the Harvard study, that parents should use one of the over-the-counter products as an initial treatment, following the package instructions. But if that product doesn't kill the lice, they're probably resistant, and further treatments will do no good.
We can't recommend Ovide, because of the lack of information on safety for young children. The active ingredients in the over-the-counter products are much less toxic to the nervous system than malathion and are not readily absorbed through the skin. Based on prior testing, the FDA labels Nix as safe for use on children older than 2 months; the other products specify no minimum age.
The safest and surest method of getting rid of lice remains the one we recommended in 1998: daily removal of lice and nits with a fine-tooth comb. It's tedious, but it's effective if you keep at it.
But before you go to the trouble, make sure your child actually has lice. Pollock reported that two-thirds of the specimens brought to his lab for testing turned out not to be lice at all, but rather debris and other insects.
Copyright © 1999-2003 Consumers Union of U.S., Inc.