Azithromycin with Magnesium Trisilicate Interaction Details

Brand Names Associated with Azithromycin

  • Azithromycin
  • Zithromax®
  • Zithromax® Single Dose Packets
  • Zithromax® Tri-Paks®
  • Zithromax® Z-Paks®
  • Zmax®

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Last updated Mar 04, 2024

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Interaction Effect

Decreased azithromycin plasma concentration

Interaction Summary

In a study of 10 healthy males, concomitant use of azithromycin regular-release capsules and an oral antacid suspension containing aluminum hydroxide and magnesium hydroxide resulted in the azithromycin Cmax being reduced by 24% compared with azithromycin alone; however, azithromycin AUC and Tmax were not affected[1]. Therefore, the manufacturer recommends that regular-release azithromycin and products that contain aluminum or magnesium not be coadministered [2]. When azithromycin extended-release oral suspension was coadministered with aluminum- and magnesium-containing antacid, there were no changes in azithromycin Cmax or AUC. Therefore, extended-release azithromycin and aluminum- and magnesium-containing antacids may be used concomitantly [3].

Severity

Minor

Onset

Unspecified

Evidence

Probable

How To Manage Interaction

Patients should be advised not to use aluminum- and magnesium-containing antacids concomitantly with azithromycin tablets or oral suspension (regular release)[2]. However, azithromycin extended-release oral suspension may be taken concomitantly with aluminum- and magnesium-containing antacids as it is not expected to affect azithromycin levels [3].

Mechanism Of Interaction

Decreased azithromycin absorption due to chelation

Literature Reports

A) Concomitant use of antacids and azithromycin regular-release capsules resulted in decreased azithromycin Cmax values compared with those seen with azithromycin alone in an open, randomized, crossover trial of 10 healthy males; however, azithromycin AUC and Tmax were unaffected. Five participants were randomized to receive azithromycin 500 mg (two 250-mg capsules) alone on day 1 and to receive azithromycin at the same dose plus a 30-mL dose of antacid (Maalox(R), aluminum hydroxide 225 mg/magnesium hydroxide 200 mg per 5 mL) on day 8. The other 5 participants received the same regimen, but in the reverse order. The mean azithromycin Cmax decreased by approximately 24% from 0.34 mcg/mL (0.45 mcmol/L) with azithromycin monotherapy to 0.26 mcg/mL (0.35 mcmol/L) when azithromycin was coadministered with the antacid. There was no effect on azithromycin AUC or Tmax [1].

B) In a study (n=39), coadministration of a single 2 g dose azithromycin extended-release oral suspension with a single 20 mL dose of an aluminum- and magnesium hydroxide-containing antacid did not affect azithromycin mean Cmax (ratio (with/without coadministered drug), 0.99; 90% confidence interval (CI), 0.93 to 1.06) and mean AUC (ratio, 0.99; 90% CI, 0.92 to 1.08) [3].

References

    1 ) Foulds G, Hilligoss DM, Henry EB, et al: The effects of an antacid or cimetidine on the serum concentrations of azithromycin.. J Clin Pharmacol 1991; 31:164-7.

    2 ) Product Information: ZITHROMAX(R) oral suspension, tablets, azithromycin oral suspension, tablets. Pfizer Labs, New York, NY, 2010.

    3 ) Product Information: ZMAX(R) extended release oral suspension, azithromycin extended release oral suspension. Pfizer Inc, New York, NY, 2008.

Azithromycin Overview

  • Azithromycin is used to treat certain bacterial infections, such as bronchitis; pneumonia; sexually transmitted diseases (STD); and infections of the ears, lungs, sinuses, skin, throat, and reproductive organs. Azithromycin also is used to treat or prevent disseminated Mycobacterium avium complex (MAC) infection [a type of lung infection that often affects people with human immunodeficiency virus (HIV)]. Azithromycin is in a class of medications called macrolide antibiotics. It works by stopping the growth of bacteria.

  • Antibiotics such as azithromycin will not work for colds, flu, or other viral infections. Using antibiotics when they are not needed increases your risk of getting an infection later that resists antibiotic treatment.

See More information Regarding Azithromycin

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Definitions

Severity Categories

Contraindicated

These drugs, generally, should not be used together simultaneously due to the high risk of severe adverse effects. Combining these medications can lead to dangerous health outcomes and should be strictly avoided unless otherwise instructed by your provider.


Major

This interaction could result in very serious and potentially life-threatening consequences. If you are taking this drug combination, it is very important to be under close medical supervision to minimize severe side effects and ensure your safety. It may be necessary to change a medication or dosage to prevent harm.


Moderate

This interaction has the potential to worsen your medical condition or alter the effectiveness of your treatment. It's important that you are monitored closely and you potentially may need to make adjustments in your treatment plan or drug dosage to maintain optimal health.


Minor

While this interaction is unlikely to cause significant problems, it could intensify side effects or reduce the effectiveness of one or both medications. Monitoring for changes in symptoms and your condition is recommended, and adjustments may be made if needed to manage any increased or more pronounced side effects.

Onset

Rapid: Onset of drug interaction typically occurs within 24 hours of co-administration.

Delayed: Onset of drug interaction typically occurs more than 24 hours after co-administration.

Evidence

Level of documentation of the interaction.

Established: The interaction is documented and substantiated in peer-reviewed medical literature.

Theoretical: This interaction is not fully supported by current medical evidence or well-documented sources, but it is based on known drug mechanisms, drug effects, and other relevant information.

How To Manage The Interaction

Provides a detailed discussion on how patients and clinicians can approach the identified drug interaction as well as offers guidance on what to expect and strategies to potentially mitigate the effects of the interaction. This may include recommendations on adjusting medication dosages, altering the timing of drug administration, or closely monitoring for specific symptoms.

It's important to note that all medical situations are unique, and management approaches should be tailored to individual circumstances. Patients should always consult their healthcare provider for personalized advice and guidance on managing drug interactions effectively.

Mechanism Of Interaction

The theorized or clinically determined reason (i.e., mechanism) why the drug-drug interaction occurs.

Disclaimer: The information provided on this page is for informational purposes only and should not be considered medical advice. Always consult with a qualified healthcare professional regarding your specific circumstances and medical conditions.

Where Does Our Information Come From?

Information for our drug interactions is compiled from several drug compendia, including:

The prescribing information for each drug, as published on DailyMED, is also used. 

Individual drug-drug interaction detail pages contain references specific to that interaction. You can click on the reference number within brackets '[]' to see what reference was utilized.

The information posted is fact-checked by HelloPharmacist clinicians and reviewed quarterly.