Felodipine and Nirmatrelvir and ritonavir interaction
Felodipine and Nirmatrelvir and ritonavir: both prescribing labels describe 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 Felodipine label · effective 2026-06-23
Coadministration of CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, erythromycin, grapefruit juice, cimetidine) with felodipine may lead to several-fold increases in the plasma levels of felodipine, either due to an increase in bioavailability or due to a decrease in metabolism.
Caution should be used when CYP3A4 inhibitors are coadministered with felodipine.
Drug Interactions CYP3A4 Inhibitors - Felodipine is metabolized by CYP3A4.
These effects have been observed with coadministration of itraconazole (a potent CYP3A4 inhibitor).
From the Nirmatrelvir and ritonavir (Paxlovid) label · effective 2026-02-19
Calcium channel blockers amlodipine, diltiazem, felodipine, nicardipine, nifedipine, verapamil ↑ calcium channel blocker Caution is warranted and clinical monitoring of patients is recommended.
The most commonly reported concomitant medications resulting in serious adverse reactions were calcineurin inhibitors (e.g., tacrolimus, cyclosporine), followed by calcium channel blockers.
If co-administered, refer to the individual product prescribing information for calcium channel blocker for further information.
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.