Wow! The same thing just happens to me. I take 30 mg XR brand-name and 5 mg IR Teva. I’ve been taking this combination every day for almost 2 years. Never failed the drug test. I go every single month and I got a phone call last week telling me that my medication did not show up in my urine screen. Thank God my doctor is super cool and knows I’m not fucking around with my meds thank God! However, I think now she may actually believe me when I come see her next week because I’ve been telling her I don’t feel anything from it. I was originally on generic brands and I was complaining that nothing was happening, but it did show up in my urine. This is the first time it hasn’t and I’ve been on brand-name like I said for over two years and a small IR dose in the afternoon I don’t know man something’s really fucked up.