Federal regulators have told the makers of the popular drugs Levitra and Zyrtec to pull some advertisements the regulators said made unsubstantiated claims. The Food and Drug Administration said Friday it sent letters this week notifying Bayer Pharmaceuticals Corp. and Pfizer Inc. that a television commercial for Levitra and three direct-mail advertisements for Zyrtec made unsubstantiated claims of superiority over competing products. In Levitra’s case, Bayer also failed to disclose FDA warnings and product information, the letter said. It was the fourth such warning for Pfizer about Zyrtec.
