Can You Take Magnesium Supplements With Azithromycin?

In our latest question and answer, the pharmacist discusses whether or not magnesium can be taken safely with azithromycin.


Can magnesium supplements be taken while taking azithromycin? What about vitamins? Are there any bad reactions or precautions or waiting time periods for taking them together?

Asked by jimmy On Jul 29, 2022

Answered by
Medical Content Reviewed By HelloPharmacist Staff

Published Jul 29, 2022
Last updated Jul 30, 2022

Key points

  • Azithromycin and magnesium-containing products should not be taken at the same time. Doing so reduces how well azithromycin is absorbed, which could affect how well it works.
  • Azithromycin should be taken at least 2 hours before, or 4-6 hours after magnesium products to avoid this interaction.


Thanks for your question!

Magnesium supplements should not be taken with azithromycin. They should be separated from one another. This includes really anything with magnesium in it, such as vitamins containing magnesium, and magnesium hydroxide, one of the active ingredients in Maalox.

Studies show that taking magnesium or aluminum-containing products could make azithromycin less effective. Essentially, both magnesium and aluminum bind to the azithromycin, which reduces overall absorption.

The prescribing information for azithromycin states very plainly to avoid the combination:

Patients should also be cautioned not to take aluminum- and magnesium-containing antacids and azithromycin simultaneously.
Zithromax Prescribing Information

Studies show that when taken with magnesium, the peak concentration of azithromycin is decreased in the body, which again, may make it not work as well. One study, which tested aluminum and magnesium-containing antacids with azithromycin, found the following results:

There were no statistically significant differences in Tmax or AUC0-48 after administration of azithromycin alone or with [magnesium-containing] antacid, but mean values of Cmax [maximum concerntration] were reduced by 24%.
J Clin Pharmacol . 1991 Feb;31(2):164-7

How Long To Separate

In order to avoid the interaction between azithromycin and magnesium, you need to separate their administration.

In terms of how long, azithromycin should be taken at least 2 hours before, or 4-6 hours after magnesium-containing products.

So, overall, you can take azithromycin and magnesium on the same day, just not together (separate them as described above).

Final Words

Thanks again for your question and feel free to reach back out again in the future!


  • Zithromax Prescribing Information, AccessFDA
  • The effects of an antacid or cimetidine on the serum concentrations of azithromycin, PubMed
  • Prescribing azithromycin, PubMed

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