Nelson Vergel
Founder, ExcelMale.com
U.S. men seeking a generic version of Viagra (sildenafil citrate) - the first and the most popular prescription drug for Erectile Dysfunction (ED) - are going to have to wait for a few more years. Viagra's patent, originally scheduled to expire in late March of 2012, has been extended to April of 2020. That's good news for the manufacturer, Pfizer, Inc.
https://www.accessrx.com/research/viagra-patent-expires/
https://www.accessrx.com/research/viagra-patent-expires/