Fesoterodine and Quinidine interaction
Fesoterodine and Quinidine: both prescribing labels flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.
Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.
What the FDA labels say
From the Quinidine (Quinidine Gluconate) label · effective 2024-08-27
Quinidine is also contraindicated in patients who, like those with myasthenia gravis, might be adversely affected by an anticholinergic agent.
Altered pharmacodynamics of other drugs: Quinidine's anticholinergic, vasodilating, and negative inotropic actions may be additive to those of other drugs with these effects, and antagonistic to those of drugs with cholinergic, vasoconstricting, and positive inotropic effects.
From the Fesoterodine (Toviaz) label · effective 2026-04-07
In poor metabolizers for CYP2D6, representing a maximum CYP2D6 inhibition, C max and AUC of the active metabolite are increased 1.7- and 2-fold, respectively.
No dosing adjustments are recommended in the presence of CYP2D6 inhibitors.
CYP2D6 Inhibitors The interaction with CYP2D6 inhibitors was not tested clinically.
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.