Flecainide and Quinidine interaction
Flecainide 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
Proarrhythmic effects Like many other drugs (including all other Class Ia antiarrhythmics), quinidine prolongs the QT c interval, and this can lead to torsades de pointes , a life-threatening ventricular arrhythmia (see OVERDOSAGE ).
Non-interactions of quinidine with other drugs: Quinidine has no clinically significant effect on the pharmacokinetics of diltiazem, flecainide, mephenytoin, metoprolol, propafenone, propranolol, quinine, timolol, or tocainide .
From the Flecainide (Flecainide Acetate) label · effective 2026-02-06
(See DOSAGE AND ADMINISTRATION ) Drugs that inhibit cytochrome P450IID6, such as quinidine , might increase the plasma concentrations of flecainide in patients that are on chronic flecainide therapy; especially if these patients are extensive metabolizers.
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.