What medications cannot be taken with azithromycin?

October 13, 2025 •

3 min read

Azithromycin has over 382 known drug interactions, with 84 classified as major. Understanding what medications cannot be taken with azithromycin is crucial for preventing potentially severe health risks, including life-threatening heart rhythm problems.

Quick Summary

Azithromycin can interact with numerous medications, leading to serious side effects. Key interactions involve drugs that prolong the QT interval, blood thinners, certain antacids, statins, and medications for heart rhythm, increasing risks of bleeding and cardiac events.

Key Points

Heart Rhythm Risks: Azithromycin should not be taken with drugs that prolong the QT interval, such as certain antiarrhythmics (amiodarone), antipsychotics (pimozide), and antidepressants, due to the risk of fatal heart rhythms.
Blood Thinner Interaction: When taken with warfarin, azithromycin can increase the risk of bleeding. Close monitoring of blood clotting levels (INR) is required.
Antacid Interference: Antacids containing aluminum or magnesium (like Maalox or Mylanta) can make azithromycin less effective. Doses should be separated by at least two hours.
Statin Complications: Combining azithromycin with statins (e.g., Lipitor, Zocor) may increase the risk of rhabdomyolysis, a severe muscle-damaging condition.
Absolute Contraindications: Certain drugs like pimozide, cisapride, and dronedarone are strictly contraindicated with azithromycin due to severe interaction risks.
Digoxin Toxicity: Azithromycin can increase the concentration of digoxin, a heart failure medication, leading to toxicity. Monitoring is necessary.
Patient Disclosure: Always inform your doctor of all medications, including over-the-counter drugs and supplements, before starting azithromycin to prevent adverse interactions.

Understanding Azithromycin and Its Role

Azithromycin, commonly known by brand names like Zithromax or as a Z-Pak, is a macrolide antibiotic prescribed to treat a variety of bacterial infections. These include skin infections, respiratory infections like pneumonia and bronchitis, and certain sexually transmitted diseases. While it is a widely used and effective antibiotic, its safety profile is contingent on avoiding interactions with other medications. In 2013, the FDA issued a safety warning highlighting the risk of potentially fatal heart rhythms, specifically QT interval prolongation, associated with azithromycin use. This risk is increased when azithromycin is combined with other drugs that affect the heart's electrical activity or its metabolism.

The Critical Risk: QT Prolongation and Heart Medications

Azithromycin can prolong the QT interval, a measure of the heart's electrical activity, potentially leading to a dangerous heart rhythm called torsade de pointes. This risk is significantly higher when taken with other medications that also prolong the QT interval.

Key interacting drug classes include:

Antiarrhythmics: Medications like amiodarone and sotalol, used for irregular heart rhythms.
Antipsychotics: Certain mental health drugs.
Antidepressants: Some, like citalopram and escitalopram, can increase the risk of an irregular heartbeat.
Other Antibiotics: Fluoroquinolones like ciprofloxacin also pose a QT prolongation risk.

Patients with pre-existing heart conditions face a greater risk.

Interactions with Blood Thinners (Anticoagulants)

Taking azithromycin with blood thinners such as warfarin may increase bleeding risk. This requires close monitoring of blood clotting levels by a healthcare provider. Report any unusual bleeding or bruising immediately.

Statins and the Risk of Muscle Damage

Combining azithromycin with statins like atorvastatin and simvastatin can increase the risk of rhabdomyolysis, a severe muscle condition. Symptoms include muscle pain, weakness, and dark urine. A doctor might recommend stopping the statin temporarily.

Reduced Effectiveness with Antacids

Antacids with aluminum or magnesium can hinder azithromycin absorption. Take azithromycin at least 1 hour before or 2 hours after these antacids.

Comparison Table of Major Azithromycin Interactions


Interacting Drug Class	Example Drugs	Potential Consequence	Management Advice
QT-Prolonging Drugs	Amiodarone, Sotalol, Pimozide, Citalopram	Increased risk of life-threatening irregular heart rhythms (QT prolongation, Torsades de Pointes).	Avoid combination if possible. Requires close cardiac monitoring if use is necessary.
Blood Thinners	Warfarin (Jantoven), Rivaroxaban (Xarelto)	Potentiates anticoagulant effect, increasing risk of serious bleeding.	Close monitoring of INR/prothrombin time is essential. Dose adjustment may be needed.
Statins	Atorvastatin (Lipitor), Simvastatin (Zocor)	Increased risk of muscle pain and severe muscle damage (rhabdomyolysis).	Monitor for muscle pain/weakness. Provider may pause statin therapy.
Antacids	Maalox, Mylanta (containing Aluminum/Magnesium)	Decreased absorption and effectiveness of azithromycin.	Administer azithromycin at least 1-2 hours apart from the antacid.
Ergot Alkaloids	Ergotamine, Dihydroergotamine	Increased risk of ergotism (vomiting, dizziness, seizures).	Avoid combination.
Digoxin	Digoxin (Lanoxin)	Azithromycin can increase digoxin levels, raising the risk of digoxin toxicity.	Monitor digoxin levels closely and adjust dose as needed.

Conclusion

Azithromycin can interact significantly with other medications, particularly those affecting heart rhythm, blood thinners, and statins, leading to potentially serious adverse effects. Antacids can also reduce its effectiveness. Always provide your healthcare provider with a complete list of all medications and supplements to screen for potential interactions before taking azithromycin.

This article is for informational purposes only and does not constitute medical advice. Always consult with a qualified healthcare professional before starting or stopping any medication.

For more detailed information from a primary source, you can review the FDA's drug safety communication on azithromycin: {Link: FDA website https://www.fda.gov/drugs/drug-safety-and-availability/fda-drug-safety-communication-azithromycin-zithromax-or-zmax-and-risk-potentially-fatal-heart}

Frequently Asked Questions

Yes, you can generally take Tums ( calcium carbonate) with azithromycin. However, you should avoid antacids containing aluminum or magnesium, like Maalox or Mylanta, or separate the doses by at least two hours as they can reduce azithromycin's effectiveness.

The most serious risk is QT prolongation, a disturbance of the heart's electrical rhythm that can be fatal. This risk is highest when azithromycin is combined with antiarrhythmics, antipsychotics, and some antidepressants.

It can be risky. Azithromycin may increase the effect of warfarin, leading to a higher risk of bleeding. If taken together, your doctor must monitor your blood clotting levels (INR) very closely.

Symptoms of a statin interaction, which can lead to rhabdomyolysis, include unexplained muscle pain, tenderness, or weakness, especially if accompanied by dark-colored urine and fever. Seek medical help if these occur.

Yes, other antibiotics that also prolong the QT interval, such as fluoroquinolones like ciprofloxacin and levofloxacin, should be used with caution to avoid an additive effect on the heart rhythm.

Medications like pimozide, cisapride, dronedarone, and thioridazine should not be taken with azithromycin due to the high risk of severe cardiac side effects.

While not a direct contraindication, drinking alcohol while on azithromycin may increase side effects like nausea and dizziness. It's generally advisable to limit or avoid alcohol to allow your body to recover from the infection.