From an FAA standpoint, migraines are a big deal, but propranolol is not.
if you can establish that your worst migraine is not in any way incapacitating, and that you just take propranolol to avoid the discomfort, then it shouldn’t be too big a deal to get an initial special issuance, (and a subsequent AME-assisted issuance on an ongoing basis)
Sorry I can’t speak to European standards, but I’d be happy to
provide any other assistance that I can...