Pfizer said it owns the patents for the drug, one of which expires in October 2019 and another in March 2012. It said in the complaint today it's suing to block generic sales until the 2019 patent expires."Generic" Viagra, of course, is easily available online, manufactured in India, China, or elsewhere. Only Pfizer-made Viagra is FDA-approved and legal for sale in the US. The question is whether that will all change in March 2012 or in 2019.
For Viagra users, it's only a price issue. Generic sildenafil citrate would cost less than the name-brand version, but it would still require a prescription.
One interesting possibility is that if Pfizer loses its patent claims, and generics hit the market in 2012, we might see Pfizer push hard to make Viagra available over-the-counter.