Flecainide and Quinine interaction
Flecainide and Quinine: the Quinine 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 Quinine (QUININE SULFATE) label · effective 2025-10-31
…disease and preexisting conduction system abnormalities, elderly patients with sick sinus syndrome, patients with atrial fibrillation with slow ventricular response, patients with myocardial ischemia or patients receiving drugs known to prolong the PR interval (e.g. verapamil) or QRS interval (e.g. flecainide or quinidine) [see CLINICAL PHARMACOLOGY ( 12.2 )] .
Although clinical drug interaction studies have not been performed, antimalarial doses (greater than or equal to 600 mg) of quinine may inhibit the metabolism of other drugs that are CYP2D6 substrates (e.g., flecainide, debrisoquine, dextromethorphan, metoprolol, paroxetine ).
Quinine sulfate is not recommended for use with other drugs known to cause QT prolongation, including Class IA antiarrhythmic agents (e.g., quinidine, procainamide, disopyramide), and Class III antiarrhythmic agents (e.g., amiodarone, sotalol, dofetilide).
Interacting Drug Interaction Drugs known to prolong QT interval (e.g., Class IA and Class III antiarrhythmic agents).
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.