The amiodarone and digoxin drug interaction is one of the most clinically important cardiovascular drug interactions to understand because it can raise digoxin exposure and increase the risk of digoxin toxicity.

In this episode of This Is Why, Dr. Busti explains why amiodarone can increase digoxin concentrations, how P-glycoprotein inhibition changes digoxin handling, and why clinicians should anticipate the need for digoxin dose adjustment and monitoring rather than react after symptoms appear.

You’ll learn why this interaction is not just a memorized warning, but a predictable pharmacokinetic and pharmacodynamic issue involving drug transport, renal elimination, cardiac conduction, and patient-specific monitoring.

Topics Covered:

Why digoxin has a narrow therapeutic window
How P-glycoprotein affects digoxin absorption and elimination
Why amiodarone increases digoxin exposure
Clinical signs of digoxin toxicity
Why nausea, fatigue, confusion, and bradycardia matter
How to think through dose reduction and monitoring
Why renal function and serum concentrations matter
Additive electrophysiologic effects on heart rate and conduction
How understanding the mechanism improves patient care

When we understand the why, we improve the how.

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Chapter Table of Contents
00:00 - Introduction
01:49 - Digoxin's Narrow Therapeutic Index
02:31 - P-Glycoprotein: The Key Transporter
04:53 - How Amiodarone Inhibits P-Glycoprotein
06:37 - Clinical Signs of Digoxin Toxicity
08:27 - Managing the Interaction
09:59 - Pharmacodynamic Effects on Cardiac Conduction
11:19 - Key Clinical Takeaways

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#Amiodarone #Digoxin #DrugInteraction #DigoxinToxicity #PGlycoprotein

Speaker:
Anthony Busti, MD, PharmD, MSc, FAHA, FNLA, is a licensed healthcare professional and medical educator with over 30 years of experience in clinical practice and academic teaching. He has trained and practiced as a nurse, pharmacist, and physician, bringing a uniquely comprehensive perspective to patient care and medical education.
Dr. Busti is dedicated to advancing evidence-based medicine and helping clinicians understand the underlying “why” behind clinical decisions to improve patient outcomes.

About This Channel:
This content is created by Anthony Busti, MD, PharmD, MSc, FAHA, FNLA, a board-certified physician with training at Johns Hopkins School of Medicine and University of Oxford and a medical educator for healthcare professionals and students. All material is based on current medical literature and evidence-based guidelines that align with principles of evidence-based medicine (EBM) and Evidence-Based Healthcare (EBHC).

Disclaimer:
This content is for educational purposes only and is not medical advice. It does not replace individualized evaluation, diagnosis, or treatment. Always seek the advice of a qualified health provider with questions about a medical condition and never delay care because of educational content.