
Yes, I had my GSD (now sadly gone) on Cyclosporin for AF for about 2 years, with a gradually decreasing dose. I didn't see any side effects at all luckily, and ultimately we were able to discontinue it without a recurrence of the AF. She was under the Queen Mother Hospital for Animals at Potters Bar.
I wish you all the luck in the world with his treatment. Hopefully if the Atopica is what is dragging him down a bit he will improve when you are able to get him off it.
Kat