My adderall (dextroamphetamine and racemic amphetamine) 10mg doesn't work anymore and I have a big test tomorrow. Is it ok to take 2 pills to equal 20mg, the dosage I need?

Need approval from. you doc, who should be informed that this dose is no longer effective--particularly important for your next refill! Assuming that you are not a dwarf, your pcp may give you the ok, as adults with ADD or ADHD may need more than the initial dose, which commonly may lose effectiveness. Higher limits are 30 mg twice a day, although most adults respond to 20 mg bid long term.