Dextromethorphan and quinidine and Nifedipine interaction
Dextromethorphan and quinidine and Nifedipine: the Nifedipine 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 Nifedipine label · effective 2026-02-05
Co-administration of multiple doses of quinidine sulfate, 200 mg t.i.d., and nifedipine, 20 mg t.i.d., increased C max and AUC of nifedipine in healthy volunteers by factors of 2.30 and 1.37, respectively.
Monitoring of heart rate and adjustment of the nifedipine dose, if necessary, are recommended when quinidine is added to a treatment with nifedipine.
Cardiovascular Drugs Antiarrhythmics Quinidine: Quinidine is a substrate of CYP3A and has been shown to inhibit CYP3A in vitro .
The exposure to quinidine was not importantly changed in the presence of nifedipine.
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.