I have a pre employment saliva drug test in 2 days. I've had one 80mg op, and 5 7.5 Norco today. I've had gastric bypass, 8 years ago, I have a prescription for the Norco, but honestly I got the cop's from a friend. I know this info isn't clear. But my question is, my prescription for my Norco is from December. How long is the prescription considered valid. As I got a printout from my pharmacy of all my meds , so I can declare them. And does the 80mg op show up as the same as the Norco because they are both opiates? Also does the gastric bypass affect how long the drugs will show up in a saliva test. If anyone has info, I would really appreciate it.