ADD medication alternative

Question

My boyfriend is 27, he was diagnosed with ADD when he was in middle school, he has taken Ritalin and Adderal but stopped because it was worsening his heart condition.
   His concentration has not helped, he is still very slow getting things done, forgets things, and has an extreemly short attention span. Are there any over the counter supplements that he can take to help him that will not induce tachycardia?