Will taking a prescribed pain pill interfere with my drug test in 2 days?

I'm not really sore if I'm supposed to post this here or not.
OK, So first things first. I have sarcoidosis and with that I have severe pleurisy. I have to take a drug test in 2 days, I usually take a darvocet for it but I'm scared cause I don't want to fail my drug test. Does anyone know how long it'll take for the meds to be out of my system? or if I'll be alright in 2 days? I do have a prescription for it I could show HR if they needed me to. I just don't want that to interfere with me getting the job I was hired for.