The maker of Ex-Lax, the country's top-selling laxative, pulled the product off store shelves Friday after the government announced it intends to ban an over-the-counter laxative ingredient linked to cancer.
Novartis Consumer Health emphasized that after more than 90 years of use in Ex-Lax, it believes the ingredient phenolphthalein is safe, but that it would reformulate the longstanding product "to avoid consumer confusion."The Food and Drug Administration did acknowledge that it has no reports that phenolphthalein has caused cancer in people.
But the FDA said animal studies found phenolphthalein, at high doses, could damage a vital gene that suppresses tumors, and consequently caused a variety of cancers in laboratory mice and rats.
The damage to the p53 gene was disturbing enough that the FDA concluded it posed a potential cancer risk to people who use phenolphthalein-containing laxatives for extended periods of time or at higher-than-recommended doses.
"It's very hard to draw a line" at which a laxative user could be at risk, cautioned FDA drug chief Dr. Robert Temple. "The concern is for long-term use, and it's greater the longer the use and the higher doses people use."
The FDA's advice: "What we're saying is find another laxative," Temple said.
Although phenolphthalein is present in Ex-Lax and a host of store-brand laxatives, the FDA noted that Americans have access to more than two dozen laxative products that do not contain the ingredient. Several Ex-Lax competitors, anticipating a ban, already have reformulated their laxatives. Bayer Corp. this summer pulled off the market its one laxative brand that contained the ingredient.
If the FDA's proposed ingredient ban becomes final, any laxative containing the compound would have to be reformulated or taken off the market. In the meantime, the FDA advised consumers to read the ingredient list on the label before buying an over-the-counter laxative.
Companies and the public may comment on the proposed ban for 30 days and then the FDA will decide whether to make the ban final.
Some 20 percent of Americans are estimated to use laxatives. The products' labels warn that over-the-counter laxatives are for occasional constipation, not for repeated or long-term use.