I am really nervous and upset about an occurance report that I was involved in. I haven't talked to my manager about it yet, but my nerves always bother me when anticipating what may happen. The incident happened the last day I worked. I came in and got report from a nurse who tends to be long winded and was trying to talk about two patients at one time just because they both had a codeine allergy. Both patients were prescribed hydrocodone for pain, so she went on to tell me that the dr switched them to oxycodone because of the codeine allergy. I didn't understand why because I have seen numerous patient's with a codeine allergy who can tolerate hydrocodone or oxycodone with no problem. So I didn't think anything of it because those were his orders. The nurse was giving both patients oxycodone for pain. One patient had orders in the computer for the oxycodone, the other patient didn't so she was charting the administration under nurses notes. So I go ahead and put the order in the computer so the administration can be charted correctly because I thought there was an order for it. We normally don't look at the charts till towards the end of our shift, unless a doctor comes and writes new orders. So while I looked in the chart I found an order for the oxycodone for one patient, but I didn't see one for the other patient. Then I thought maybe the doctor told her to give the oxycodone and d/c the hydrocodone, but he didn't write the order and she didn't either. I did find where she d/c the hydrocodone and wrote the administration in nurses notes. I didn't remember to pass this information along in report to the next nurse, so I get a phone call later saying there wasn't an order and the doctor didn't know about it. So I'm involved in an occurance report because it's a huge medication error and patient safety issue and I'm afraid of loosing my license and my job.