The drugmaker said Tue. the FDA gave it approval to make a cheaper version of Pfizer's (PFE) drug Revatio, and it's begun shipping it. Revatio treats high blood pressure in lung arteries and had U.S. sales of $338.7 mil last year. A day earlier, rival Watson Pharmaceuticals (WPI) said it had gotten an OK to make a generic version of Revatio. The main ingredient in Revatio is sildenafil citrate, the top ingredient in Pfizer's blockbuster sexual dysfunction drug Viagra, although Viagra has larger doses. Mylan (MYL) shares rose 0.4% to 26.15. Pfizer fell 0.3% to 24.05.