PBY,
Welcome to HealthBoards. You'll find lots of support here.
Go to WebMD.com, or to diagKNOWsis.org and find their drug search tools. You can input the names of each of the drugs and find out what they side-effects or interaction problems can be. That might give you more information.
Or -- I have no idea what your instructions are for taking the drugs, but if it's possible to skip a few days with the new drug, and see what happens to your symtoms, it would be a way of gaining more knowledge. Don't skip any doses unless you get permission from the doctor first.
You might also try posting to the drug interactions board, or the stroke or heart disease boards, where people may have experience with your particular drugs.
Good luck -- keep us posted.