Was this med prescribed by your doctor for that purpose? If so, you should discuss the side effects with him/her.
As for the surgery, they always ask what meds you take. Do mention this to them and also how it makes you feel. They need to know which meds might be in your system before they do anesthesia. I don't know the half life of propranolol but still say something to them. They'll sort it out.
(Well, shoot. . .I see you posted this 6 hours ago and you're probably not even home to see this response. These time zones are a nuisance. Hope it all worked out for you. And do ask about the med and side effects)
I can't answer you question, but just wanted to wish you good luck today and I hpe you have a sppedy recovery
michelle