* To be available from March
* Over 40 mln adults suffer from allergies in U.S. - Sanofi
(Adds detail from statement)
PARIS, Jan 25 (Reuters) - Sanofi-Aventis (SASY.PA) has won U.S. regulatory clearance to sell its Allegra allergy treatment as a drug patients can get without prescription, it said on Tuesday.
The so-called over-the-counter version, which will become available in March, comes after Sanofi bought Chattem last year to expand in consumer healthcare.
Allegra used to be a blockbuster drug for Sanofi, selling at least $1 billion a year, but has lost its patent protection, clearing the way for cheaper generics to appear on the market. (Reporting by Caroline Jacobs; Editing by James Regan)