What happens if you take a prescribed drug and it shows up on a drug test? Should you tell the person giving the drug test about the prescribed medications?
What happens if you take a prescribed drug and it shows up on a drug test?
That depends on the goals of the test and of the specific prescribed drug in question.
In some cases you will "fail" the test. In other cases, it won't matter.
Should you tell the person giving the drug test about the prescribed medications?
Yes. Before taking the test, you should tell the drug tester about any prescribed medications that you suspect might influence the test.
When I was drug tested, the form specifically asked that you list all prescribed medication you are currently taking.
Note that you are never required to tell anyone what medications you are taking. Many prescribed drugs wouldn't impact the test at all. You could choose not to disclose your medicines and hope that it doesn't cause the test to be failed.
Absolutely. First, you should be telling them the total list of every medication you are taking, just because that's usually a good idea when dealing with medical professionals.
Second, you should tell them so you can directly ask them whether any of these drugs will cause false-positives for any of the tests they are running.
At the very least, if you are explaining to HR "I failed the meth test because I take Metfromin", you are much better off if HR looks at the drug test report and it says right in the report "patient claims to be taking Metformin, which would generate a false positive for meth". Otherwise HR is barely aware that can cause that, and is more likely to just assume you're on meth and say "Next!"
It also helps the lab. There are several ways to screen for a drug. If their usual test confuses Metfromin and meth, and they have an alternate test which distinguishes them, you have given them a heads-up to use it. In some cases that is simply impossible; an example is medically necessary steroids vs. the anabolic steroids that are prohibited in high competitive sports. (Maybe you're interviewing at a sports company with a high sports culture).
Someone (likely HR) will contact you to let you know you've failed the test and ask for an explanation. This is when you would bring in your prescription bottle and explain why it shouldn't be an issue. They may ask for a doctor's note to confirm, but that's not very likely.
The person administering the test doesn't particularly care what medications you take. They just need to make sure you take the test according to the process and provide results to your employer (their client).