In my dealings as a Safety Professional onsite at Power Plants, I handled all my contractors drug testings and if it anyone tested hot on whatever they were taking, it was automatic 3 days off and maybe more once the test as sent to a lab for final tests to ensure you prescription was being taken as prescribed. They can tell if you are taking it right by the amount that's in your urine. You would have to provide your prescription and a letter from your doctor before returning for work. If you test as abusing the prescription you were fired and dismissed from any other work at any other Power Plants too. Tough rules but they are.I was told that some of the Vets are selling theirs, rather then taking them..I told them that I only took them if I needed it..VA said that not how they roll, must take them as prescribed..Whether you need them or not at the time