it all depends on the med... Antibiotics are processed by your liver, as is alcohol so the two will fuck your liver big time, same with tylenol. A benzo, barbs, and muscle relaxants will potentiate alcohol, so as long as you dont over do it your fine, if you do its coma time tho. If in doubt ask a seasoned pill popper or check the enzymes which process said medicine and see they dont cross the same pathways as alcohol (or any other shit for that matter). Or just smoke pot and be 100% safe, thats my motto.