Anything that is four (or more) years old is likely expired and probably going to be useless at this stage. Please be careful about disposal, though.I have bottles of the same from years ago I never touched. Who cares. I have Norco 5mg which doesn’t work, but 10mg is better. I also have bottles of the strong stuff (OxyContin) and some Vicodin from my previous surgery four years ago I keep for an emergency