Vardenafil (INN) is a PDE5 inhibitor used for treating erectile dysfunction that is sold under the trade names Levitra (Bayer AG, GSK, and SP), Staxyn in India, and Vivanza in Italy. ==History== Vardenafil was co-marketed by Bayer Pharmaceuticals, GlaxoSmithKline, and Schering-Plough under the trade name Levitra. As of 2005, the co-promotion right... Found on http://en.wikipedia.org/wiki/Vardenafil