5 Mylanta Side Effects and How to Manage Them

Mylanta is one of the most popular over-the-counter (OTC) product lines used to treat heartburn, bloating, and gas. Some Mylanta products contain the antacid aluminum, while others have calcium. Many also have magnesium and an antigas medication called simethicone.

Each Mylanta product may contain slightly different ingredients and amounts, with different instructions.

Side effects aren’t common with Mylanta, but they’re still possible. Here’s an overview of what to expect.

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Mylanta side effects at a glance

Mylanta side effects are often mild and can be managed at home. Others, while less common, may require assistance from your healthcare team.

Mild Mylanta side effects include:

• Nausea

• Diarrhea

• Constipation

• Feeling tired or weak

• Loss of appetite

Less common but potentially serious Mylanta side effects include:

• High magnesium levels

• High aluminum levels

Let’s review five Mylanta side effects you should know about and what you can do if they occur.  

EXPERT PICKS: WHAT TO READ NEXT

• Mylanta dosage: Mylanta’s ingredients and amounts can vary by product. Get a breakdown of Mylanta products and the specific dosage of each one.

• Over-the-counter remedies: Mylanta is one over-the-counter option for relieving an upset stomach. Here’s when to take Mylanta, Pepto, Tums, and more to manage your symptoms.

• Quick relief: Learn how to get rid of heartburn fast — from medications to home remedies.

1. Nausea

Mylanta may cause you to feel mildly nauseous. While uncommon, this may be due to simethicone, an ingredient in many Mylanta products. Your nausea may also be from the acid reflux or upset stomach that you’re treating. So, it may help to avoid or minimize foods and drinks that can worsen these symptoms, including spicy foods, fried foods, and coffee.

Many medications can cause nausea, and it usually goes away without any treatment. Plus, Mylanta products are typically only taken for a short period of time. That helps limit side effects such as nausea.

If your nausea is bothersome or you start vomiting, speak with your healthcare team. They can help you figure out the cause and how best to manage it. 

2. Diarrhea

Diarrhea is another potential side effect of Mylanta products that contain magnesium. Some products contain more magnesium than others. So, it helps to check the OTC “Drug Facts” label to see how much magnesium you’re taking.

Diarrhea from Mylanta is usually mild and goes away without any treatment. If you experience diarrhea, drink plenty of fluids to help prevent dehydration. It may also help to limit or avoid foods that can worsen diarrhea, such as dairy products and fatty foods. Those may have been the foods that caused you to reach for Mylanta in the first place.

If your diarrhea is bothersome or persistent, stop taking Mylanta to see if that helps. Your pharmacist can help you find magnesium-free options to manage your symptoms. But if your diarrhea continues or gets worse after stopping Mylanta, check in with your healthcare team.

3. Constipation

Constipation is a possible side effect of Mylanta products with aluminum. It may be more likely if you’re taking Mylanta regularly. If Mylanta is making you constipated, this side effect usually resolves on its own once you stop taking it.

Some of the same tips used to manage heartburn symptoms can also help with constipation. Eating high-fiber foods, drinking plenty of fluids, and getting enough physical activity are just a few examples.

Still experiencing constipation with Mylanta? Talk to your pharmacist about aluminum-free alternatives that may be less likely to cause constipation. Reach out to your healthcare team if you’re unable to get relief after stopping Mylanta.

4. Too much magnesium

As mentioned above, Mylanta products contain magnesium. And the amount can vary between products. While uncommon, it’s possible for magnesium levels in the blood to get too high while taking Mylanta, leading to magnesium toxicity.

Your kidneys play an important role in removing excess magnesium from the body. If you have kidney problems, you may be more likely to develop high magnesium levels from Mylanta. In this case, be sure to talk to your healthcare team before taking it.

If your magnesium gets too high, you might have symptoms such as dizziness or lightheadedness, flushed skin, or nausea and vomiting. Tell your healthcare team right away if you develop these symptoms. In serious cases, trouble breathing, an irregular heartbeat, and fainting can occur. Seek emergency medical attention if this happens.

5. Too much aluminum

Similar to high magnesium levels, using Mylanta products may also lead to too much aluminum in your body, especially if you have kidney problems. This can often cause constipation. But very high aluminum levels is a medical emergency that requires prompt action.

Severe symptoms of aluminum toxicity can include:

• Weakness

• Tremor

• Difficulty speaking

• Confusion

• Seizures

If you or someone you know may be experiencing aluminum toxicity, go to the nearest ER for evaluation.

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Written by:

Brian Leonard, PharmD, BCACP, BCGP

Brian Leonard earned his doctorate in pharmacy from the University of Florida College of Pharmacy and is board certified in Ambulatory Care and Geriatric Pharmacy.

Edited by:

Alyssa Billingsley, PharmD

Alyssa Billingsley, PharmD, is the director of pharmacy content for GoodRx. She has over a decade of experience as a pharmacist and has worked in clinical, academic, and administrative roles.

Reviewed by:

Austin Ulrich, PharmD, BCACP

Austin Ulrich, PharmD, BCACP, is a board-certified ambulatory care clinical pharmacist. In his early career, he provided direct patient care in a variety of settings, including hospital and community pharmacies, and in a primary care clinic as a clinical pharmacist.

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