A Comprehensive Guide: What Should You Avoid When Taking Digoxin?

October 9, 2025 •

3 min read

Digoxin has a narrow therapeutic index, meaning the dose required for therapeutic effect is very close to a toxic dose. Understanding what should you avoid when taking digoxin is crucial for safety and efficacy in treating conditions like heart failure and atrial fibrillation.

Quick Summary

Taking digoxin requires careful management of your diet, medications, and supplements. Certain substances can alter its effectiveness or increase toxicity risk, including diuretics, NSAIDs, St. John's Wort, and high-fiber foods.

Key Points

Medication Interactions: Many drugs, including diuretics, NSAIDs, certain antibiotics, and other heart medications like amiodarone, can dangerously alter digoxin levels.
Herbal Supplements: Avoid St. John's Wort, as it can drastically decrease digoxin's effectiveness; stopping it suddenly can cause a toxic spike.
Dietary Fiber: High-fiber foods and supplements (like bran and psyllium) can reduce digoxin absorption. Separate doses from high-fiber meals by at least 1-2 hours.
Black Licorice: Real licorice containing glycyrrhizin can deplete potassium, significantly increasing the risk of digoxin toxicity and irregular heartbeats.
Electrolyte Balance: Low potassium, low magnesium, or high calcium levels increase the risk of digoxin toxicity. Diuretics can often cause these imbalances.
Toxicity Symptoms: Be aware of signs of toxicity: nausea, confusion, vision changes (yellow/green halos), and changes in heart rate or rhythm.
Communication is Key: Never start or stop any other medication or supplement without first consulting your doctor or pharmacist due to the high risk of interaction.

Understanding Digoxin and Its Sensitivity

Digoxin is a cardiac glycoside medication used to treat heart failure and certain irregular heartbeats like atrial fibrillation. It works by strengthening the heart muscle's contraction, slowing the heart rate, and improving the filling of the heart's ventricles with blood. Because digoxin has a narrow therapeutic range, small changes in its blood concentration can lead to either reduced effectiveness or toxicity. Toxicity is a significant concern and can be influenced by factors like kidney function, electrolyte levels, and interactions with other substances. Patients taking digoxin need regular monitoring, and knowing what to avoid is crucial for safe treatment.

Medications to Avoid or Use with Caution

Many medications can interact with digoxin. Always inform your doctor and pharmacist about all medications you are taking.

Drugs That Can Increase Digoxin Levels

These medications can raise digoxin levels, potentially causing toxicity. Symptoms include nausea, vomiting, confusion, vision changes, and serious heart rhythm issues. Key examples include antiarrhythmics (like amiodarone, quinidine, and verapamil), certain antibiotics (like clarithromycin), NSAIDs, and some calcium channel blockers (like diltiazem). Diuretics are often prescribed with digoxin but can lower potassium and magnesium, increasing toxicity risk even at normal digoxin levels.

Drugs That Can Decrease Digoxin Levels

These substances can reduce digoxin absorption, making it less effective. Examples include antacids containing aluminum or magnesium, certain cholesterol-lowering medications like cholestyramine, some chemotherapy drugs, and metoclopramide. Taking antacids and digoxin at least two hours apart is often advised.


Interaction Type	Interacting Substance/Class	Effect on Digoxin	Management Advice
Increased Risk of Toxicity	Diuretics (e.g., furosemide)	Can cause low potassium, increasing digoxin's toxic effects.	Regular monitoring of electrolyte levels is essential.
Increased Risk of Toxicity	Antiarrhythmics (e.g., amiodarone, quinidine)	Markedly increase digoxin blood levels.	Dose adjustments and close monitoring are required.
Increased Risk of Toxicity	NSAIDs (e.g., ibuprofen)	Can increase digoxin levels, especially with poor kidney function.	Check with a doctor before regular use.
Decreased Effectiveness	High-Fiber Foods / Supplements (e.g., bran, psyllium)	Reduce absorption of digoxin.	Take digoxin at least 1-2 hours apart from high-fiber meals.
Decreased Effectiveness	Antacids	Reduce intestinal absorption.	Separate doses by at least 2 hours.
Variable / Dangerous	St. John's Wort	Can significantly decrease digoxin levels, reducing its effect. Stopping it can cause levels to rise dangerously.	Avoid this combination.
Variable / Dangerous	Black Licorice	Can lower potassium levels, increasing risk of toxicity.	Avoid real licorice containing glycyrrhizin.

Dietary and Herbal Supplement Interactions

Certain foods and herbal supplements can impact digoxin therapy.

Foods to Monitor

High-fiber foods, especially insoluble bran fiber found in oatmeal and high-fiber cereals, can reduce digoxin absorption. Taking digoxin at least one hour before or two hours after a high-fiber meal can help. Real black licorice contains glycyrrhizin, which can lower potassium and significantly increase the risk of digoxin toxicity and dangerous irregular heartbeats. Grapefruit juice may slightly increase digoxin levels, but this is usually not considered clinically significant. Be cautious with salt substitutes containing potassium and potassium-rich foods like bananas, especially if taking diuretics, and discuss this with your doctor.

Herbal Supplements to Avoid

Many herbal supplements should be avoided due to potential interactions. St. John's Wort can drastically lower digoxin levels and effectiveness; stopping it suddenly can cause a toxic spike. Ginseng may increase digoxin levels. Hawthorn's safety with digoxin is unclear. Herbs with laxative effects, like senna, can cause potassium loss and increase toxicity risk. Plants containing cardiac glycosides, such as lily-of-the-valley or foxglove, should also be avoided due to additive toxicity risk.

Conclusion: Prioritizing Safety Through Communication

Managing digoxin therapy requires close collaboration with your healthcare team due to its narrow therapeutic index and numerous potential interactions. Always consult your doctor or pharmacist before starting, stopping, or changing any medication, OTC product, or supplement. Be vigilant for early signs of toxicity, such as loss of appetite, nausea, vision changes, or an irregular pulse, and report them immediately. By understanding what you should avoid when taking digoxin and maintaining open communication with your healthcare provider, you can help ensure safe and effective treatment.

For more detailed information from an authoritative source, you can visit MedlinePlus.

Frequently Asked Questions

St. John's Wort can significantly decrease the amount of digoxin in your blood, making it less effective. If you stop taking St. John's Wort suddenly, your digoxin levels can rise to a dangerous, toxic level. It is best to avoid this combination.

Yes, but you should time them carefully. High-fiber foods like bran cereals, oatmeal, and psyllium supplements can reduce the absorption of digoxin. It is recommended to take digoxin at least one hour before or two hours after eating high-fiber foods.

Real black licorice contains glycyrrhizin, a substance that can lower your body's potassium levels. Low potassium dramatically increases the risk of digoxin toxicity, which can cause severe irregular heartbeats.

Early signs of digoxin toxicity are often nonspecific and can include loss of appetite, nausea, vomiting, and diarrhea. Neurological symptoms like confusion and visual disturbances (such as blurred vision or seeing yellow-green halos around objects) are also common.

You should check with your doctor first. Nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen can increase digoxin levels in the blood, raising your risk of toxicity, especially if you have kidney problems.

Not necessarily. The interaction with potassium-rich foods like bananas is complex. Some medications taken with digoxin (like certain diuretics) cause potassium loss, making bananas helpful. However, if your potassium is normal or high, too much could be an issue. Always discuss your diet with your doctor.

Antacids can decrease the absorption of digoxin. To avoid this interaction, you should take any antacids at least two hours before or two hours after you take your digoxin dose.