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Aluminum/magnesium antacids are used to help relieve symptoms of an upset stomach, heartburn, acid indigestion, sour stomach, gas, or feeling bloated. They are usually well tolerated, but you may have diarrhea or constipation when taking them. Do not take more than the recommended dose. Aluminum/magnesium antacids come in many different forms. Ask your health care provider if you are not sure which product to take. Tell your health care provider about all of your health conditions and any medicines you take.

Uses

What are aluminum/magnesium antacids used for?

Aluminum/magnesium antacids are commonly used to help relieve the following symptoms. 

These uses may vary depending on the specific aluminum/magnesium antacid you are taking. 

Aluminum/magnesium antacids may also be used for other conditions as determined by your health care provider.

How do aluminum/magnesium antacids work (mechanism of action)?

Aluminum/magnesium antacids work to reduce symptoms of upset stomach, heartburn, bloating, or gas in a few ways. The active ingredients in most aluminum/magnesium antacid products are aluminum hydroxide, various forms of magnesium, and/or simethicone. Some products may have other ingredients, such as calcium carbonate, in addition to or instead of these ingredients. Always check the label to see what ingredients your product has.

Aluminum hydroxide, various forms of magnesium, and calcium carbonate are antacids that work by neutralizing stomach acid. This helps reduce indigestion, heartburn, or sour stomach. Simethicone is an antigas medicine that works by helping small gas bubbles in your gut come together. This can make it easier for gas to pass through your gastrointestinal (GI) tract, which can help relieve pressure and bloating.

How are aluminum/magnesium antacids supplied (dosage forms)?

Brands and other names

  • Gaviscon
  • Maalox
  • Mylanta

Dosage forms and strengths

Aluminum/magnesium antacids come in various dosage forms and strengths that are taken by mouth. They may include a variety of ingredients, such as aluminum hydroxide, various forms of magnesium, and simethicone. Some products may have other ingredients, such as calcium carbonate, in addition to or instead of these ingredients. Always check the label to see what ingredients your product has.

How should I store aluminum/magnesium antacids?

Storage requirements may vary among aluminum/magnesium antacids. Aluminum/magnesium antacids should generally be stored at room temperature, between about 68 F and 77 F (20 C and 25 C). Avoid freezing and keep the container tightly closed. Storage requirements for some aluminum/magnesium antacids may not be provided with the product packaging. If you are not sure how to store your aluminum/magnesium antacid, ask your pharmacist.

Side Effects

What are the most common side effects of aluminum/magnesium antacids?

The most common side effects of aluminum/magnesium antacids are listed below. Tell your health care provider if you have any of these side effects that bother you.

  • Diarrhea (usually from magnesium)
  • Constipation (usually from aluminum)
  • Stomach cramps
  • Decreased appetite
  • Nausea

There may be other side effects of aluminum/magnesium antacids that are not listed here. Contact your health care provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088 (800-332-1088). In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of aluminum/magnesium antacids?

While less common, the most serious side effects of aluminum/magnesium antacids are described below, along with what to do if they happen.

Severe Allergic Reactions. Aluminum/magnesium antacids may cause allergic reactions, which can be serious. Stop taking aluminum/magnesium antacids and get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the face, lips, mouth, tongue, or throat
  • Trouble swallowing or throat tightness
  • Itching or skin rash
  • Bumps on the skin called hives that can be red, pink, white, or brown depending on your skin tone
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain

Warnings & Precautions

Who should not use aluminum/magnesium antacids?

Allergies to Ingredients. People who are allergic to any of the following should not take aluminum/magnesium antacids.

  • Aluminum hydroxide
  • Gaviscon
  • Maalox
  • Magnesium
  • Mylanta
  • Simethicone
  • Any of the ingredients in the specific product

Your pharmacist can tell you all of the ingredients in the specific aluminum/magnesium antacid products they stock.

What should I know about aluminum/magnesium antacids before using them?

There are multiple forms of aluminum/magnesium antacids, and they may have different ingredients or be taken in different ways. If you are not sure which aluminum/magnesium antacid product to take, talk to your health care provider. 

Read and follow the directions on your aluminum/magnesium antacid package or take it as recommended by your health care provider. Do not take more than the recommended dose. Do not take the maximum dose for more than two weeks unless your health care provider tells you to. Taking too much can cause side effects. 

If you are taking an aluminum/magnesium antacid liquid, follow any instructions about shaking it well before measuring your dose. This helps in making sure that you get the right amount of medicine. Use an accurate measuring device to measure your dose. A household spoon is not an accurate measuring device and may cause you to take the wrong dose. Ask your pharmacist which measuring device to use.

Aluminum/magnesium antacid liquids may have a chalky taste. To reduce this, you may be able to mix them with water or milk. If you have questions about how to do this, talk to your pharmacist.

If you are taking an aluminum/magnesium antacid chewable tablet, chew it completely before swallowing. You should usually drink a full glass of water after each dose. 

If you still have heartburn or other gut-related symptoms for two weeks or longer, stop taking aluminum/magnesium antacids and contact your health care provider. They may recommend a different medicine or want to see if something more serious is going on. 

Aluminum/magnesium antacids may affect how other medicines work. You may need to take them at a different time than other medicines. Your health care provider can let you know when to take each medicine.

Keep aluminum/magnesium antacids out of the reach of children.

Aluminum/magnesium antacids may have a laxative effect. This means your poop may be loose, watery, or more frequent. This may be more common if you are taking an aluminum/magnesium antacid often or at high doses. Talk to your health care provider if you have concerns.

If you have phenylketonuria (PKU), make sure you read the aluminum/magnesium antacid label to check the ingredients. Some products may have phenylalanine in them, which can be dangerous for people with PKU. If you have any questions about which product you can take, talk to your pharmacist.

What should I tell my health care provider before using aluminum/magnesium antacids?

Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them know if aluminum/magnesium antacids are right for you.

In particular, make sure that you discuss any of the following.

Current and Past Health Conditions. Tell your health care provider if you have any of the following.

Low-Magnesium or Low-Sodium Diet. Tell your health care provider if you are on a low-magnesium or low-sodium diet. Your health care provider will let you know if you should take aluminum/magnesium antacids if you have dietary restrictions.

Other Medicines and Supplements. Aluminum/magnesium antacids may interact with other medicines and supplements. Before taking aluminum/magnesium antacids, tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.

Pregnancy. Ingredients in aluminum/magnesium antacids can vary by product. Tell your health care provider if you are pregnant or plan to become pregnant. Your health care provider will let you know if you should take aluminum/magnesium antacids while you are pregnant or trying to get pregnant.

Breastfeeding. Ingredients in aluminum/magnesium antacids can vary by product. Tell your health care provider if you are breastfeeding or plan to breastfeed. Your health care provider will let you know if you should take aluminum/magnesium antacids while breastfeeding.

Interactions

Do aluminum/magnesium antacids interact with foods or drinks?

There are no known interactions between aluminum/magnesium antacids and foods or drinks.

It is unknown if drinking alcohol will affect aluminum/magnesium antacids, but alcohol can lead to heartburn or other stomach problems. It is best to limit the amount of alcohol you drink while you are taking aluminum/magnesium antacids.

Do aluminum/magnesium antacids interact with other medicines (drug interactions)?

Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

Aluminum/magnesium antacids may affect the absorption of many other medicines. Check with your health care provider and tell them about all medicines that you take or have recently taken. 

Does interact with other drugs you are taking?

Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally use too much of an aluminum/magnesium antacid?

If you or someone else has used too many aluminum/magnesium antacids, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of aluminum/magnesium antacids?

Aluminum/magnesium antacids are meant to be used only when needed. Take them according to the package directions or as recommended by your health care provider. Do not take double or extra doses.