July 1 (Bloomberg) -- Bayer AG’s health-care unit filed a lawsuit to prevent Teva Pharmaceutical Industries Ltd. from selling a copy of the erectile dysfunction pill Levitra.

Teva is seeking U.S. Food and Drug Administration approval to sell a generic version of the drug. Leverkusen, Germany-based Bayer Schering Pharma is seeking a court order to prevent the FDA approval until a patent expires in 2018.

Levitra, first approved by U.S. regulators in 2003, is sold by Schering-Plough and GlaxoSmithKline Plc in the U.S. and competes with Pfizer Inc.’s Viagra and Eli Lilly & Co.’s Cialis. The drug, whose active ingredient is vardenafil hydrochloride, generated $341 million in sales last year for Bayer, the company said in its annual report.

Denise Bradley, a spokeswoman for Petak Tikva, Israel-based Teva, said the company has no comment on the suit, which was filed today in federal court in Wilmington, Delaware. Teva is the world’s biggest generic-drug maker.

In its application with the FDA, Teva contends that it won’t infringe any valid or enforceable patent on the medicine. Under federal law, Bayer’s suit triggers an automatic 30-month period in which the FDA can’t approve Teva’s application, unless a judge rules in the generic-drug maker’s favor before then.

In January, the consumer group Public Citizen warned that Levitra, Viagra and Cialis may lead to dangerous side effects if combined with one of 56 common medicines. It posted an online list of prescription drugs and herbal remedies to avoid when taking any of the three medicines.

The case is Bayer Schering Pharma AG v. Teva Pharmaceuticals USA Inc., 09cv480, U.S. District Court, District of Delaware (Wilmington).

To contact the reporter on this story: Susan Decker in Washington at sdecker1@bloomberg.net.

Last Updated: July 1, 2009 18:02 EDT