Mylan Laboratories said U.S. regulators approved its generic version of Sanofi-Aventis' sleeping pill, Ambien, in the 5 mg and 10 mg strengths.
In a statement, the generic drug maker said the product is being shipped immediately.
Ambien had sales of about $2.2 billion in the U.S. for the same strengths for the 12-month period ending Dec. 31, 2006, according to IMS Health.
Sanofi-Aventis lost patent protection for Ambien on April 21. Ambien dominates the U.S. sleeping pill market, which is growing at about 10% a year.