Does orange juice with Vyvanse matter, or only vitamin C tablets?

Orange juice with lisdexamfetamine is not the same situation as megadose vitamin C tablets. Amphetamine excretion is pH-dependent. Acidifying agents such as ascorbic acid can increase urinary excretion and may decrease amphetamine levels; that is labelled for lisdexamfetamine and amphetamines. 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/00075816.PDF https://www.camh.ca/en/professionals/treating-conditions-and-disorders/adult-adhd/adult-adhd---treatment/adult-adhd---pharmacotherapy https://www.caddra.ca/medication-chart/