I've been in this boat for over a year. It depends on the drug/situation, but if you're just taking a basic antibiotic as a precaution after an operation, drinking alcohol negates the effects of the drug and you're essentially wasting money on pills. It sucks during the holidays (I'm on them right now), but all you can do is bite the bullet and be diligent in taking your prescription every day and you won't end up being put back on them three times in a row due to infection...