Perrigo Co. (PRGO) has acquired the exclusive U.S. rights to sell and distribute over-the-counter generic versions of the popular allergy drug Allegra.

The store-brand pharmaceutical and nutritional products maker didn't detail how it obtained the rights to sell the drug, and Perrigo representatives weren't immediately available for comment.

Perrigo said it now has the rights to sell and distribute over-the-counter fexofenadine HCl 180-milligram and 60-milligram tablets as well as fexofenadine HCl 60-milligram and pseudoephedrine 120-milligram tablets--the generic versions of Sanofi-Aventis SA's (SNY, SAN.FR) Allegra and Allegra D-12 products, which are used to treat seasonal allergies. Teva Pharmaceutical Industries Ltd. (TEVA) currently has prescription approval for those products.

The rights to many generic versions of blockbuster drugs are set to come up for grabs soon as patents expire--a situation that has left drug makers looking for ways to bolster their product pipelines to replace lost revenue.

Perrigo in April said its fiscal third-quarter profit rose by one-third as the company's sales and margins rose.

Shares of Perrigo closed at $59.30 on Monday and were inactive premarket. The stock has more than doubled in the past year.

-By Nathan Becker, Dow Jones Newswires; 212-416-2855; nathan.becker@dowjones.com