From Drugs.com:
You should not use propranolol if you are allergic to it, or if you have:
asthma
history of slow heart beats that have caused you to faint
severe heart failure (that required you to be in the hospital)
a serious heart condition such as "sick sinus syndrome" or heart block (2nd or 3rd degree, unless you have a pacemaker).
Still, a thoughtful suggestion brother.
Sure, of course…. Ever read a bottle of aspirin for side effects or ibuprofen? lol, trust me , it’s all the same.
It’s a beta blocker, like many many other BP meds . If you don’t have asthma, no worries ( beta receptors when stimulated cause bronchodialation, so blocking them could create bronchoconstriction in theory, which is esssntially what asthma is)
2nd degree heart blocks: extremely rare. A 21 year old kid for sure doesn’t have a 2nd degree heart block. High heart blocks like this are caused mostly by MI’s ( heart attacks)
3rd degree heart blocks : this isn’t a thing, this is a lethal heart rhythm you can’t even live with. This is an emergency and not something someone just “goes into”. Again, definitely not a 21 year old kid.
heart failure: again, not a 21 year old kid.
Sick sinus syndrome: extremely, extremely uncommon. And mostly again, in the elderly.
Just wanted to point these things out, you can read the side effects or contraindications and be scared out of your mind on just about anything. While there are real reasons not to use propranolol, outside of a HX of asthma, none of them apply to a 21 year old kid in the least. Propranolol is an extremely safe medication, especially at low doses for exactly the type of scenario the OP is talking about, and is extremely common.