According to the reference data, it is generally safe to take over-the-counter medications for colds while taking ADHD medications. However, it is best to avoid antihistamines if the ADHD medication is an amphetamine like Adderall or Dexedrine, as they may counteract the sedative effect of the amphetamine and pose a danger. There are no known interactions between ADHD medications and over-the-counter cold medications like diphenhydramine (Benadryl).