Dextromethorphan and quinidine and Digoxin interaction
Dextromethorphan and quinidine and Digoxin: the Dextromethorphan and quinidine prescribing label describes an interaction that usually calls for monitoring, a dose change, or spacing the doses.
Usually manageable with monitoring or a dose change. Tell your pharmacist you take both.
What the FDA labels say
From the Dextromethorphan and quinidine (Nuedexta) label · effective 2026-01-22
Digoxin: Increased digoxin substrate plasma concentration may occur.
Plasma digoxin concentrations should be closely monitored in patients taking NUEDEXTA concomitantly, and the digoxin dose reduced, as necessary.
Digoxin Quinidine is an inhibitor of P-glycoprotein.
Concomitant administration of quinidine with digoxin, a P-glycoprotein substrate, results in serum digoxin levels that may be as much as doubled.
Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.
Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.