FDA Rejects NRDC Petition to Ban Lindane

Miriam E. Tucker

December 05, 2012

WASHINGTON — The US Food and Drug Administration (FDA) has rejected a citizen petition from the Natural Resources Defense Council to ban lindane-containing lice and scabies treatments from the US market.

"In what should have been a fairly easy decision to follow the law and remove a drug from the market that is neither safe nor effective, the FDA...has instead ignored the clear science and denied NRDC's 2010 petition to ban the dangerous drug lindane," wrote NRDC co-petitioner Mae Wu, JD, in a blog post on the environmental organization's Web site.

The decision probably will not have much of a practical impact, however, because US physicians rarely use lindane. In 2009, the American Academy of Pediatrics (AAP) stopped recommending the product for the treatment of lice or scabies, even as second-line therapy, Michael T. Brady, MD, chief of the AAP's Committee on Infectious Diseases, told Medscape Medical News.

"I think that, given in the United States we have a number of different options that seem to be working well, it would be unusual that a pediatrician would even consider it," said Dr. Brady, chair of the Department of Pediatrics at Nationwide Children's Hospital, Columbus, Ohio.

Warnings and Bans

Lindane (gamma-hexachlorocyclohexane) has been used as both an agricultural pesticide and a pharmaceutical to treat head lice (1% shampoo) and scabies (1% lotion).

In 2003, the FDA required a black box warning on the lindane label emphasizing its potential for neurotoxicity, particularly in infants, children, the elderly, individuals with other skin conditions, and those weighing less than 110 pounds. It advised that lindane only be used in patients who cannot tolerate or have failed other first-line treatments for lice and scabies and that it only be used a single time.

The state of California banned the use of lindane in pharmaceutical products in 2002 because of concerns about the product contaminating the water supply. Since then, other states have also moved to restrict or ban pharmaceutical use of the product.

In 2006, the Environmental Protection Agency stopped allowing lindane's use in agriculture, citing its toxicity to both people and the environment.

In 2007, the FDA sent a warning letter to lindane manufacturer Morton Grove Pharmaceuticals, citing the company for false safety and efficacy claims for its lindane shampoo and lotions, marketed under the brand name Kwell.

In 2009, the agency again revised lindane's label, this time noting that serious adverse effects, including seizures and deaths, had been reported.

Lindane was targeted for elimination by the Stockholm Convention on Persistent Organic Pollutants in 2009 and has also been addressed in several other international treaties.

The NRDC's citizen petition cited those facts, among others, in support of its position that pharmaceutical products containing lindane be banned. It also cited evidence for lack of efficacy.

In addition, the petition noted, "Head lice is not a life-threatening condition, and rarely is scabies life-threatening. With other alternatives that are more effective, non-toxic, and less expensive, the continued approval of lindane as a treatment for head lice and scabies is unnecessarily dangerous."

FDA Response

In the FDA's reply letter, signed by Janet Woodcock, MD, director of the FDA's Center for Drug Evaluation and Research, the agency did not dispute most of the facts laid out by the NRDC but, rather, said that the group's petition "had not provided new or persuasive evidence that lindane's risk-benefit profile has changed such that FDA should find that the benefits of the product, when used as currently labelled, outweigh the risks."

The number of dispensed prescriptions for lindane has dropped by 91% since 2002, and the agent currently accounts for only 2% of the prescription pediculicide and scabicide market in the United States, Dr. Woodcock noted.

Head lice can be difficult to treat because drug resistance is common and treatment often requires multiple rounds of therapy, she said.

In addition, scabies, although generally not life-threatening, can involve the entire body below the neck, cause intense itching, and render some individuals vulnerable to secondary infections.

"Although there are several products available to treat scabies, there is evidence that scabies has developed resistance to different therapies," Dr. Woodcock noted, adding that the disease is a particular problem for people who are immunocompromised.

Permethrin, the first-line prescription treatment for scabies, has a failure rate of about 10%. Aside from lindane, there is only one other approved drug for scabies, crotamiton, and that has a failure rate of 40%. "If lindane were to be removed from the market, patients would have very limited options for treatment of scabies, especially given the failure rate of other FDA-approved drugs," she said.

Going Forward

Indeed, Dr. Brady told Medscape Medical News, "I think it's not that [the FDA] is expecting people are actually using lindane right now, but if you completely eliminated it, then if by some chance in the future it's needed it wouldn't be available."

However, he said that the AAP takes no position on whether the product should remain on the market. "FDA has a more regulatory function to determine how they want to manage the issue.... We would want to limit our role to provide advice how to treat patients, and we wouldn't include lindane in any of our recommendations."

The NRDC plans to continue to pursue the ban, Wu told Medscape Medical News.

Wu and Dr. Brady have disclosed no relevant financial relationships.

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