Well, your doc's a doc, so I guess he has his reasons! Sometimes when a primary med isn't working as well as we'd like, docs add on a secondary med (usually something milder) to see if anything happens. Is your anxiety situational (tests, certain events, etc? beta-blockers like propranolol help with that)? I'd try it and see what happens. You'll know very quickly whether it helps or not. Beta-blockers start to work in less than an hour, but you may have to already feel anxious to feel any different; different people have different responses. These drugs are generally considered very safe, lots of people are on them: anxious people, people with high blood pressure, elderly people trying to keep their hearts healthy. The drugs have been around for a long time and have a good track record. Side effects include: slow heartbeat, cold extremities, lightheadedness especially upon standing. Not everyone has all those, and some go away after your body adjusts to the medication. Best wishes.