It is probably a good idea to mention your nephrectomy to every medical professional you deal with, even the dentist, just to be on the safe side. I know it's annoying because then that leads to other questions and the whole "omg your gesture was so altruistic and yaddy ya" and then at least for me I feel bad because it feel as though I'm bragging. But your health and ensuring that everybody on the same page is very important.
As an aside, I took Celexa for a few years (well before donating) and it was very mild in terms of side effects and little to no withdrawal. in fact, taking Celexa is what allowed me to get off Effexor (quitting that, is basically like quitting heroin in terms of violence of the symptoms), but quitting Celexa was just a matter of lowering the dose over a couple of months. The one thing I would see as potentially problematic is the side effect of weight gain. Some people put on quite a few pounds whilst on antidepressants and that could have effects on blood pressure, eventually.