Amantadine and certain antidepressants are said to help some people affected by AD(H)D as well. But talk to your doctor before you go "oh, amantadine is cheap otc flu med...". And it depends on a lot of factors, like your exact symptoms (with/without hyperactivity), treatment goals, side effects and secondary problems. Really really talk to a doctor about this, getting "the meds" right is complicated and takes some trial and error.