My mum was on fentanyl after a major operation. She was hallucinating and thought the nurses were stealing her money she even rang the police on her mobile it was so bad my sister stayed with her for 3 nights to stop her trying to get out of the window on the 4 th floor. This lasted for days they didn't give any prior warnings we'd thought she'd lost he marbles. She told me she had seen death and didn't want to go.
Bloody scary I can tell you. She now has absolutely any recollections of the events