Pfizer sues to protect Viagra from generic competition

NEW YORK — Pfizer has sued Torrent Pharmaceuticals in an effort to protect its erectile-dysfunction drug Viagra (sildenafil citrate) from generic competition, according to a Bloomberg News report published Tuesday. 

Torrent has filed an aNDA with the Food and Drug Administration, challenging Pfizer's patent that expires on Oct. 22, 2019. 

According to the report, Pfizer and Teva Pharmaceuticals USA have reached a settlement that permits Teva to market a generic version of Viagra in the United States on Dec. 11, 2017.