Adderall is an amphetamine and will show up on a drug test as such. If you have a legitimate prescription, then it won't be a problem. It should not be detectible in your system after 2-3 days of not taking it. Claritin D is an antihistamine that reduces the natural chemical histamine in the body. Histamine can produce symptoms of sneezing, itching, watery eyes, and runny nose.

The only reason both of these substances combined will fail a drug test is because Claritin D is used to make Methamphetamines. Normal people that are prescribed Adderall and Claritin will have a harder time passing a drug test, unless they can prove otherwise. The question then becomes will Meth heads have the best excuse and will have time to get off Meth for the next drug test.