Well, let's see: we'll have a rapid increase in population from lagging deaths, increased fertility rates, so i'd say overpopulation will become a huge problem (Malthus, anyone?). We'd need to rapidly update our infrastructure to deal with such issues, completely overhaul our planning and laws to deal with such issues, whether it be social security and welfare policies to retirement planning, to incarceration.
Then, of course, there could be the psychological issue - we've seen this before: the guy becomes old and all his loved ones die as time progresses (Interview with the vampire, twilight - hey, don't judge - etc...). how would one cope with losing his friends/loved ones how either could not afford or would not want such medication? Not to mention humans have not been designed to live that long, so that merits the question: how long until you get sick of life? would you want to extend your life to a point where suicide might be a better option, rather than living another 30 years?
Sorry, but I'm not sure how i can see this working out for the better