Nowadays it's completely different; they give you a big fat cylinder of morphine - mine was safety-pinned to my nightie - with a tube into your hand, controlled by a big button. When you want a shot of morphine you press the button. I had this after my recent surgery and after my appendectomy in 1993. You can have as much as you like.
OK, I assume that the regulating device has some kind of fail-safe so that you can't give yourself too much, but I never found out. Simply being in control of your own pain relief means you relax, and you only use it sparingly. You can cope with discomfort, knowing it will never become agony. And after a couple of days the side-effects - feeling sleepy and numb and sometimes nauseous - outweigh the benefits, and you spontaneously ease off the stuff. The nurses would come and check it and say 'huh, you've hardly used any'. By Sunday I was pestering them to take the tube out of my hand.
This goes against received wisdom about opiates and people having control of their own drugs, and I assume this is why this style of pain relief is fairly new, although morphine has been around for, what, 150 years?
I know that long term pain presents its own challenges, and could lead to addiction through desperation, but I think that for short and medium term pain, and for terminal patients, more or less complete control of pain relief should be given. For long term pain, perhaps the kind of relief could be cycled to prevent addiction (I'm a bit ignorant here).
I also think that the majority of adults could handle legalisation of Class A narcotics, because - heck - I had total access to as much of the stuff as I wanted, and I got bored with it in about 48 hours.