They are usually only checking for illegal drugs with a pre-employment UA. The only prescription drugs that I can think of that would show up on this type of screen are opiates and if you're lucky enough to live in So. California and have a prescription for marijuana. It should say on your paperwork what type of test you'll be taking - 5 panel or 10 panel. I can't think of all the drugs they test for on these, but you can do a google search and get your answer. Personally, I think you'll be fine.