Answer:

There is no generic viagra or cialis availiable oficially in USA or Canada local pharmacies yet. But there are some countries that do not follow FDA and produce the so called generic viagra and cialis.
In chemical substances there is probably no big difference. Works same both of them. same as generic cialis. Unfortunately has same side effects as brand meds for some people. But the biggest difference I think is in price and that’s about it. also, if anyone orders generic meds online there is MUCH bigger chance to get ripped than ordering brand meds, so people should be really careful doing it and order only from trusted sources. a good site is viagrafans.com . it is an online community of viagra cialis levitra users. the site has also got price comparison for cheapest reputable generic and brand pharmacies.