Pain Management. On Oxycodone, Hydrocodone. Is That Safe?

I just recently went to a pain management appointment and I was drug tested I was told that I wouldn't recieve a prescription for my pain till the results came back they should b back by monday or tuesday. I have been prescribed 10mg oxycodone for the past year and a half in another state and I am trying to avoid having to get off them cold turkey. I was given a perscription of 15 oxycodone by my primary care doctor to last me till monday but I was told by the nurse at the pain management clinic that it may take till tuesday or wedsday till my results come back. I'm contimplating taking hydrocodone 7.5s tomorrow and friday morning to help me save enough of my oxycodone to get me through. I don't know if i will be drug tested again but just to b safe i would like to know how long the hydrocodon will take to get out of my system?