Propranolol and historic asthma

I've been suffering terribly with anxiety/panic attacks for the last three weeks. Pounding heart, etc. I've had ecg and blood tests. Dr now wants to put me on propranolol. I'm very anxious about taking them (any medication really), as I had asthma for a few years mid 30's until about 10/12 years ago and not used an inhaler since. To be fair, it was never very bad. Has anyone had or got experience of historic asthma and now taking propranolol? I'm supposed to be picking them up later. Many thanks.