Disopyramide and Flecainide interaction
Disopyramide and Flecainide: 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 Disopyramide (Norpace) label · effective 2026-08-24
…asymptomatic non-life-threatening ventricular arrhythmias who had had a myocardial infarction more than 6 days but less than 2 years previously, an excessive mortality or non-fatal cardiac arrest rate (7.7%) was seen in patients treated with encainide or flecainide compared with that seen in patients assigned to carefully matched placebo-treated groups (3.0%).
The average duration of treatment with encainide or flecainide in this study was 10 months.
…asymptomatic non-life-threatening ventricular arrhythmias who had had a myocardial infarction more than 6 days but less than 2 years previously, an excessive mortality or non-fatal cardiac arrest rate (7.7%) was seen in patients treated with encainide or flecainide compared with that seen in patients assigned to carefully matched placebo-treated groups (3.0%).
Considering the known proarrhythmic properties of Norpace or Norpace CR and the lack of evidence of improved survival for any antiarrhythmic drug in patients without life-threatening arrhythmias, the use of Norpace or Norpace CR as well as other antiarrhythmic agents should be reserved for patients with life-threatening ventricular arrhythmias.
As with other Type 1A antiarrhythmics, disopyramide phosphate has been associated with torsade de pointes.
From the Flecainide (Flecainide Acetate) label · effective 2026-02-06
Because both of these drugs have negative inotropic properties and the effects of coadministration with flecainide acetate are unknown, neither disopyramide nor verapamil should be administered concurrently with flecainide acetate unless, in the judgment of the physician, the benefits of this combination outweigh the risks.
There has been little experience with the coadministration of flecainide acetate and either disopyramide or verapamil .
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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.