Co-Q10 is not a drug per se. It is an antioxidant that your body produces and that statins destroy. I'd stop statins before stopping Co-Q10 (not that I'm telling YOU to stop statins - that decision is for you to make).

Here's an article on how much Co-Q10 to take to counteract statins and how it may be helpful in other situations as well.
http://www.drweil.com/drw/u/ART0336...-Q10-CoQ10.html