Antihistamines like Benadryl or Reactine and stimulants. Interaction or myth?

Antihistamines such as diphenhydramine (Benadryl) and cetirizine (Reactine) are not proven to block Concerta as an internet interaction myth. Diphenhydramine is sedating and can worsen grogginess for some people, including the next morning, and it can affect driving. Cetirizine is less sedating for many people, though some still feel drowsy. If the change is persistent, distressing, or affecting daily functioning, bring a brief timeline to the prescribing clinician rather than changing the dose independently. References: https://pdf.hres.ca/dpd_pm/00077178.PDF https://www.nhs.uk/medicines/methylphenidate-adults/ https://www.camh.ca/en/professionals/treating-conditions-and-disorders/adult-adhd/adult-adhd---treatment/adult-adhd---pharmacotherapy