Propranolol is a beta blocker usually used for hypertension whereas benzodiazepines are usually used for anxiety or occasionally for epilepsy or a muscle relaxer. Unless you tend to have low blood pressure it shouldn't be harmful to take them together as long as you are taking them as prescribed. If you're worried just don't take them together, wait an hour between the two and for peace of mind you can check with your doctor or pharmacist. But I used to be on propranolol and xanax together...also was on valium and metaprolol together...no problems.