First of all, I totally agree with the other three comments.
You did the right thing.
I am so proud of you. I know it is hard. Hard is not even a word to describe it.
Now you've got experience with a diverting/addicted nurse. It will happen to you again, probably... and maybe more than one time. This is way more common that you think.
Think about what would have happened if you had not told your manager? Everyone would continue to pretend that everything is alright. She would continue to get high and potentially kill herself eventually. She would require more and more narcotics as time went on. Maybe you just really started noticing it right now because she is requiring more now.
When a person is addicted to IV narcotics like this, there is a fine line between walking around normal and being passed out in the bathroom from too much. I'm sure she was taking way more than the legal dose. Heck, none of it was legal,, but she was steps away from taking a lethal dose. THink about how bad you would feel right now if you didn't say something,, and she was found in the bathroom, dead?
Or think about if you didn't say anything and a patient ended up having a severe reaction to a narcotic...... because a nurse AFTER this nurse ACTUALLY GAVE THE PATIENT the dose that was documented and was never given by this addicted/diverting nurse??
This is nothing new. It has happened in countless hospitals, on countless units. The reason you are bothered so much by it is because of many things.
She probably seemed like the super nurse, didn't she? She was probably nice to everyone, right? She probably was a really nice person that would go out of her way to help you and everyone else, right? She would stay late, come early,, sign up for extra shifts, right? These are all characteristics of the diverting nurse.
She has serious issues with herself and her home life and in NO WAY ARE YOU TO BLAME FOR ANY OF THIS!
Don't lose anymore sleep over this. As a matter of fact, you should be sleeping better after this. Get rid of your guilt. You did an honorable thing. And most importantly, you did what you had to do. Don't ever put your license in jeopardy over something like this. That's exactly what you would have been doing if you let this slide. So what if she was transferring to a new position and would not have access to narcotics. I seriously doubt that it would have lasted very long, she would have figured out a way to get her narcotics. She would have gotten another part time job, or eventually wiggled her way back into working overtime on a unit somewhere,,, or she would have gotten someone else's password. Or she would have started looking to buy on the street, from your friendly corner store drug dealer.
You cannot control this kind of nurse,, the ONLY way you can help them is to report the facts to your supervisor. I was always taught to never approach this kind of person and tell them they need help. They won't get it, and then they will run and hide from you and anyone that tries to help.
So, please, trust me when I tell you that you did the right thing, you did the only thing that you could do. You did what any good nurse would do.
Since you work at a unionized hospital, then most likely they will not fire her. She will go to rehab and get help. Then she will come back in a few months sober. She won't have access to narcotics for a while, and she will be drug tested frequently. She will be getting the counseling that she needs and the tools she needs to fight her addiction. Please don't shun her, she is only human, and she has a disease. IF she is strong enough to fight it, and has the courage to come back to work sober,, she deserves another chance.