Flecainide

300 interactions 706 cited references

Also sold as: Tambocor®

About Flecainide

Flecainide is an antiarrhythmic medication used to prevent certain life-threatening irregular heartbeats. Read the full Flecainide drug information page →

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS · Updated Aug 9, 2026 · Editorial policy · Data sources

Sources: FDA prescribing information (Structured Product Labeling), the published literature cited in each entry, DDInter 2.0 (a major open-access drug-interaction database), and legacy DrugBank interaction data distributed by the NIH's RxNav service (decommissioned in 2024) — analyzed and reviewed by our pharmacist team. How we build this library →

Most serious with: Pimozide Ritonavir Mesoridazine Piperaquine Nirmatrelvir Mavorixafor

18 Contraindicated 270 Major 11 Moderate 1 Minor

All (300) Contraindicated (18) Major (270) Moderate (11) Minor (1)

Major

Flecainide Imipramine An increased risk of cardiotoxicity (QT prolongation, torsades de pointes, cardiac arrest) Details Flecainide Inotuzumab Ozogamicin Besponsa Increased risk of QT interval prolongation Details Flecainide Isoflurane Fluriso An increased risk of cardiotoxicity (QT prolongation, torsades de pointes, cardiac arrest) Details Flecainide Isradipine DynaCirc® An increased risk of cardiotoxicity (QT prolongation, torsades de pointes, cardiac arrest) Details Flecainide Itraconazole Sporanox An increased risk of QT interval prolongation and torsade de pointes Details Flecainide Ivabradine Corlanor Increased risk of QT prolongation Details Flecainide Ivosidenib Tibsovo An increased risk of QT interval prolongation Details Flecainide Ketoconazole Extina Increased risk of QT interval prolongation Details Flecainide Lacosamide Motpoly An increased risk of AV block, bradycardia, and ventricular tachyarrhythmia Details Flecainide Lapatinib Tykerb An increased risk of QT interval prolongation Details Flecainide Lefamulin Xenleta Increased risk of QT interval prolongation Details Flecainide Lenvatinib Lenvima Increased risk of QT-interval prolongation Details Flecainide Leuprolide Eligard Increased risk of QT interval prolongation Details Flecainide Levofloxacin Levaquin Increased risk of QT interval prolongation Details Flecainide Lidocaine Akten An increased risk of cardiotoxicity Details Flecainide Lidoflazine An increased risk of cardiotoxicity (QT prolongation, torsades de pointes, cardiac arrest) Details Flecainide Lisdexamfetamine Arynta Increased dextroamphetamine or lisdexamfetamine (prodrug of dextroamphetamine) exposure and an increased risk of serotonin syndrom... Details Flecainide Lofexidine Increased risk of QT interval prolongation Details Flecainide Lonafarnib Zokinvy An increased risk of QT interval prolongation and torsade de pointes Details Flecainide Loperamide Diamode An increased risk of QT interval prolongation, which may increase risk of cardiotoxicity (torsade de pointes, cardiac arrest) Details Flecainide Lorcainide An increased risk of cardiotoxicity (QT prolongation, torsades de pointes, cardiac arrest) Details Flecainide Lumefantrine Increased CYP2D6 substrates exposure and an increased risk of QT prolongation Details Flecainide Macimorelin Increased risk of QT interval prolongation Details Flecainide Mefloquine Lariam® An increased risk of cardiotoxicity (QT prolongation, torsades de pointes, cardiac arrest) Details Flecainide Mercaptopurine Purinethol® An increased risk of hepatotoxicity Details Flecainide Methadone Diskets Increased QT interval prolongation, increased methadone exposure and an increased risk of opioid adverse effects Details Flecainide Methotrexate Jylamvo Increased methotrexate exposure, an increased risk of methotrexate-related severe adverse reactions, reduced active metabolite for... Details Flecainide Metolazone Increased risk of electrolyte imbalance and subsequent cardiotoxicity Details Flecainide Metronidazole Flagyl An increased risk of QT interval prolongation Details Flecainide Mifepristone Korlym An increased risk of QT interval prolongation Details Flecainide Milsaperidone An increased risk of QT interval prolongation Details Flecainide Mirtazapine Mirataz Increased risk of QT interval prolongation and torsades de pointes Details Flecainide Mobocertinib Exkivity An increased risk of QT interval prolongation Details Flecainide Moxifloxacin Avelox Increased risk of QT interval prolongation Details Flecainide Nelfinavir Viracept Increased risk of QT interval prolongation Details Flecainide Nilotinib An increased risk of QT interval prolongation Details Flecainide Norfloxacin An increased risk of QT interval prolongation Details Flecainide Nortriptyline An increased risk of cardiotoxicity (QT prolongation, torsades de pointes, cardiac arrest) Details Flecainide Octreotide Bynfezia An increased risk of cardiotoxicity (QT prolongation, torsades de pointes, cardiac arrest) Details Flecainide Ofloxacin Floxin® An increased risk of QT interval prolongation Details

Check another drug

Still have questions about this combination?

Every question gets a real answer from a licensed pharmacist — free, and usually within a day.

Ask the pharmacist

Educational information only, not medical advice. Always confirm interactions with your pharmacist or prescriber before making any change to your medications.