Which is the latest sildenafil drug?

Viagra (sildenafil) Viagra is the only brand of sildenafil which is not yet available as a generic. Sildenafil is a pde-5 inhibitor. All pde-5 inhibitors are only available in the states as brands, not generics. Compare cialis, levitra, (vardenafil) staxyn & stendra to viagra. What's best for you may not be best for someone else but as a class, they all have the same benefit & side effect profile. And none can be taken w/nitrates.