HAir follicle test and a prescription for flexeril. Will this cause a problem?

Ok so my hubby is up for a REALLY good job. They do a hair follicle test....(which is no big deal because he does't use any drugs) He does have a couple prescriptions for flexeril that he takes when he needs it for spasms in his back. A nurse friend of ours said that they test for benzodiazepines and that flexeril is clified under that. So now he is in a panic thinking this may prevent him from getting the job. I told him it's his prescription so it's okay, but he is still worried. Should he bring in the prescription before the test? Is it something that they will even test for for pre-employment? Or should he just take it and if they say he failed take the prescription in? This job will change our life and he doesn't want something like this to prevent him from getting it. He is trying to get ahold of someone at the office to see what he should do but can't get ahold of anyone that knows because they don't work for the lab. I just think it would be unfair for him to lose a chance because of something a Dr. gave him to use. Anyways, just wondering if anyone has been through this. THANKS IN ADVANCE! :)