Can You Take Antacids With Your Antibiotic?

In our latest question and answer, the pharmacist discusses why taking antacid products with your antibiotic can result in a significant interaction.


I have been told to take amoxicillin 3 times a day for a chest infection. This is the 5th round of antibiotics and the infection has never cleared. I take Gaviscon liquid for heartburn quite often at the same time as my antibiotic. Should I stop taking the Gaviscon or not have it at the same time?

Asked by Sugar Plum On Aug 25, 2022

Answered by
Medical Content Reviewed By HelloPharmacist Staff

Published Aug 25, 2022
Last updated Apr 15, 2024

Key points

  • Antacids can interact with several classes of antibiotics, including tetracyclines and fluoroquinolones.
  • Calcium, aluminum, and magnesium-containing antacids should be separated from most antibiotics. Be sure to ask your doctor or pharmacist if your drugs are safe to combine.


It is generally recommended not to combine antacid medications (e.g. Gaviscon, Maalox, Tums, etc...) with antibiotics. While not every antibiotic interacts with antacids, many do, so it is important to talk to your doctor or pharmacist before combining them.

In simple terms, the ingredients in commonly used antacid products can bind to an antibiotic, and decrease absorption,  making them less effective and potentially causing treatment failure.

The antacids of concern are ones that contain any of the following ingredients:

  • Calcium Carbonate
  • Aluminum Hydroxide
  • Magnesium Carbonate

Interaction In Detail

Calcium, aluminum, and magnesium are well known to combine, or 'chelate' with many antibiotic medications. Chelation simply refers to a metal ion/compound (e.g. calcium) binding to a non-metal ion/compound (e.g. an antibiotic). Once an antibiotic is chelated, the oral absorption of the product is often significantly reduced, resulting in reduced antibiotic concentrations in the blood. This has to potential to cause a situation where you do not absorb a dose large enough to be effective in eradicating your infection.

It's not just the metals in antacids that can affect your medication but foods that contain calcium, aluminum or magnesium can as well. This is why many medication labels will indicate that they should not be taken with dairy or other calcium-containing foods.

How Long To Separate

If you are taking an antibiotic that is known to interact with the compounds mentioned above, it is generally recommended that the antibiotic should be taken either 2 hours before or 6 hours after taking the potentially interacting agent. 

If you have been consuming the antacid Gaviscon, which contains aluminum and magnesium, there is a good chance it has been binding with your antibiotic medications, making them less effective. Below, are some common medication classes known to interact with calcium, aluminum, and magnesium:

Calcium, Magnesium, Aluminum Antacid Interaction With Antibiotic Class

The following antibiotics have been reported to interact with calcium, aluminum, and magnesium-containing antacids.

  • Tetracyclines (e.g. tetracycline, doxycycline)
  • Fluoroquinolones (e.g. Levaquin, ciprofloxacin)
  • Macrolides (e.g. azithromycin)
  • Cephalosporins (e.g. cefpodoxime, cefuroxime)

It should be noted that not all antacids contain calcium, magnesium, or aluminum. H2 blockers, like Zantac (ranitidine) and Pepcid (famotidine), as well as PPI drugs, like Prilosec (omeprazole) and Prevacid (lansoprazole), do not contain those interacting ingredients.

Final Words

Please be sure to speak with your doctor/pharmacist regarding all the medications you take to avoid any additional interactions.

If you have any questions about a specific antibiotic or antacid, let us know! We'll be more than happy to help.


  • Adverse antibiotic drug interactions, PubMed
  • Effects of antacids on the clinical pharmacokinetics of drugs. An update, PubMed
  • Cefuroxime antacid interactions, PubMed
  • Interactions between ciprofloxacin and antacids--dissolution and adsorption studies, PubMed

About the Pharmacist

Dr. Brian Staiger, PharmD

Dr. Brian has been practicing pharmacy for over 13 years and has wide-ranging experiences in many different areas of the profession. From retail, clinical, program development, and administrative responsibilities, he's your knowledgeable and go-to source for all your pharmacy and medication-related questions! Dr. Brian Staiger also has herbalist training and educational certificates in the field of medical ethnobotany. Feel free to send him an email at [email protected]! You can also connect with Dr. Brian Staiger on LinkedIn. The list of questions & answers below are authored by Dr. Brian Staiger PharmD.

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