This is the danger of taking verbal orders from anyone, especially from those you don't have a long-standing, trusting relationship with... and even then, if it comes down to your job or theirs, they may suffer from cloudy memory in order to save themselves.
The current state of over-supply of nurses makes RNs fairly disposable--that's the unfortunate consequence of far too many grads for too few positions. You're replaceable; someone is waiting in the wings to take your job as soon as you collect your last paycheck.
Things like this (the PA back peddling and denying that she gave a verbal) don't happen unless there was a subsequent problem. And, that problem could have been anything from the patient complaining of itching to the patient dying. So, no matter how minor or major the issue, the PA is going to cover her butt and claim you didn't have an order. And, the problem is you didn't have an order (well, OF COURSE you had an order, but not one you can prove). In a 'worst case' this goes to court and you're sitting on the witness stand trying to explain to a jury of non-medical folks that the PA told you to give a narcotic... the hospital's lawyer or the deceased patient's lawyer is going to ask you where that piece of paper was. Then he/she is going to pull out all the hospital’s rules and regulations about verbal orders, and all the laws about dispensing narcotics, and all the lessons you got in nursing school
about ‘the right patient, the right drug…” No matter how much you try to explain, you’ll look worse and worse. And in the event of this ‘worst case’ scenario, the hospital will distance itself from you to save itself. So, early on, far before this goes to court (if it ever would) the hospital will protect itself and claim this is not standard procedure and you had no right to act independently. They may very well be doing this ‘distancing dance’ now.
If it were so easy to refuse all verbal orders, we’d do so. But, that brings a different risk: the risk of delay in providing urgent or emergent care to the patient. Refusing to carry out verbal orders denies the patient of quality care. Refusing verbal orders also risks your job as you’d be seen as difficult and uncooperative.
We always want justice and it’s in our culture to believe the good guy always wins. Sadly, this isn’t the case. There is no perfect solution—and maybe not even an acceptable solution. You were caught in a no-win situation. Appeal to your union, alert your malpractice carrier, and talk to your supervisor. Best of luck.