Drug interactions
Flecainide + Pentamidine
Severity: Major
Flecainide and Pentamidine: major interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Pentamidine, especially when given intravenously, can prolong the QT interval and cause torsade de pointes. Flecainide adds proarrhythmic and conduction-slowing effects, so the combination increases the risk of serious arrhythmia.
What this interaction means in plain words
Flecainide and Pentamidine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Flecainide belongs to Cardiovascular; Pentamidine belongs to Anti Parasitic.
Why it happens
Additive effects on cardiac repolarization and conduction.
What to do
Avoid the combination where possible, for example by choosing another antiarrhythmic or antimicrobial. If it must be used, monitor ECG and correct electrolyte abnormalities and hypoglycemia risk.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Flecainide and Pentamidine, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 7 days on the web. No card needed.
Other interactions of Flecainide
- Flecainide + Nirmatrelvir Contraindicated
- Flecainide + Nirmatrelvir / ritonavir Contraindicated
- Flecainide + Pimozide Contraindicated
- Flecainide + Ritonavir Contraindicated
- Flecainide + Thioridazine Contraindicated
- Flecainide + Tipranavir Contraindicated
Other interactions of Pentamidine
- Clomipramine + Pentamidine Contraindicated
- Desipramine + Pentamidine Contraindicated
- Dronedarone + Pentamidine Contraindicated
- Moxifloxacin + Pentamidine Contraindicated
- Nortriptyline + Pentamidine Contraindicated
- Pentamidine + Pimozide Contraindicated
Frequently asked questions
Can I take Flecainide with Pentamidine?
MediHelp rates the interaction as major. Flecainide and Pentamidine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Pentamidine, especially when given intravenously, can prolong the QT interval and cause torsade de pointes. Flecainide adds proarrhythmic and conduction-slowing effects, so the combination increases the risk of serious arrhythmia.
How serious is the interaction between Flecainide and Pentamidine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination where possible, for example by choosing another antiarrhythmic or antimicrobial. If it must be used, monitor ECG and correct electrolyte abnormalities and hypoglycemia risk.
What other medicines interact with Flecainide?
MediHelp also lists interactions of Flecainide with, for example, Nirmatrelvir, Nirmatrelvir / ritonavir, Pimozide. The full list is on the Flecainide page.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
