There really is no definitive answer to this question.
I've been on these medications for many many years and I have had no problems with drinking.
This is a personal preference. I would say if you haven't had experience on drinking on these before, I would keep it light. Don't drink too much without knowing how your body is going to respond. When you have a better idea of how you respond, you will know where your cutoff is going to be.
My advice, enjoy a few drinks - don't get wasted.