If poison expires it becomes safer
If medicine expires it becomes poison
Not necessarily.
Aspirin yes, paracetamol no.
Some medicine also just becomes less effective, not more dangerous.
In the case of tetracycline antibiotics the degradation products can damage the kidneys and cause Fanconi syndrome. So in that case as a medicine for people it becomes poison, as a poison for bacteria it becomes safer.
If you wait long enough does poison expire and become medicine again tho?
Less poisonous. Its purpose is to be poison.
Only one way to know
less. go to sleep
Surely it’d be less effective since some of the molecules or whatever have broken down into (hopefully) less poisonous molecules?
Presumably yes, and for historical context look to Napoleon Bonaparte. It’s presumed that when he attempted suicide the mercury cyonide had “expired” (humidity and water got in) and that’s why his suicide failed. I still wouldn’t go around eating expired poison to prove a point though.