I think they are only valid for a week after opening but we have loads left. Yes he has floppy ears. Would it harm if it’s out of date? We have spent a fortune on various illnesses since Christmas. Two upset tummy’s, one eye infection and now two ear infections.
I've used out of date drops on Ddog who seems to have an infection everytime they even look at a river or pond. Human antibiotics are generally still okay even if they're well out of date (as in less potent bug better than nothing at all).