There is a very odd feature of our physiology that is related to opioids. If an individual is actually in extreme pain, they can tolerate doses of morphine that would kill a user ingesting it for pleasure. If someone is enduring long term chronic pain they don’t get addicted in the same way that fools on the street shooting it up for pleasure do. Perhaps because in that case it’s working to alleviate pain, not produce euphoria, though the sudden reduction in pain itself probably feels euphoric. They didn’t give me much in the way of opioids when my back was injured. Mostly lovely Darvon which they took away (off the market) because 1/10th of 1 percent of pregnant women had a bad side effect.
I had a self dosing button after surgery. Not sure what it was, but it went into the IV and I think it was morphine. My nurse friend said that was most likely as it is the “gold” standard for that purpose. Lasted a few days.
When they took out the IV and switched to pills-the nurse told me to ask for the next pain dose at least an hour before the estimated timeframe for dosage. Because it usually would take them that long to get around to doing anything, and I’d be ready to climb the walls.
Most of the pills for pain - I can’t take without first taking anti-nausea meds. And if I am taking it at home, I cut the pain pill in half, and wait to see if It’s going to be enough.