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Overview: Calcium antacids are taken to help relieve indigestion, heartburn, or a sour stomach. If you have these symptoms for more than two weeks, you should talk with your health care provider. Common side effects of calcium antacids include constipation, gas, and feeling bloated. There are several forms of calcium antacids. 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 calcium antacids used for?

Calcium antacids are commonly taken to help relieve the following symptoms. 

Calcium antacids may also be taken for other conditions as determined by your health care provider.

How do calcium antacids work (mechanism of action)?

Calcium antacids neutralize acid in your stomach. This helps reduce indigestion, heartburn, or sour stomach.

What forms of calcium are typically used as antacids for heartburn, sour stomach, or acid indigestion?

  • Calcium carbonate
  • Calcium phosphate

Some calcium forms are used as supplements. See Calcium Supplements for more information.

How should I store calcium antacids?

Storage requirements may vary among calcium antacids. Calcium antacids should generally be stored at room temperature, between about 68 F and 77 F (20 C and 25 C). Storage requirements for some calcium antacids may not be provided with the product. If you are not sure how to store your calcium antacid, ask your pharmacist.

Side Effects

What are the most common side effects of calcium antacids?

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

There may be other side effects of calcium 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 calcium antacids?

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

Severe Allergic Reactions. Calcium antacids may cause allergic reactions, which can be serious. Stop taking calcium 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 calcium antacids?

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

  • Calcium
  • Caltrate
  • Citracal
  • Os-Cal
  • Oysco
  • Oyster shell calcium
  • Rolaids
  • Tums
  • Viactiv
  • Any of the ingredients in the specific product

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

What should I know about calcium antacids before using them?

There are multiple forms of calcium antacids and they may be taken in different ways. Some calcium antacids may work better for you than others. Some calcium antacids may be better tolerated than others. If you have any questions, talk to your health care provider.

Read and follow the instructions for the product you have and make sure you understand how to take it properly. 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 calcium can cause side effects.

Keep calcium antacids out of the reach of children.

If you have symptoms for more than two weeks, talk with your health care provider. They may want to check to see if something more serious is going on.

If you are taking a chewable calcium antacid, be sure to chew it well before swallowing it. 

If you are taking a liquid calcium antacid, read the label to see if you should shake it well before measuring your dose. 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 what measuring device to use.

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

If you have phenylketonuria (PKU), be sure to check the ingredients in calcium antacid labels before taking one. Some chewable calcium antacids may contain phenylalanine, which can be dangerous for people with PKU. Ask your pharmacist if you need help finding a calcium antacid that is safe for you to take.

What should I tell my health care provider before using calcium 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 calcium 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-Calcium Diet. Tell your health care provider if you are on a low-calcium diet. Your health care provider will let you know if you should take a calcium antacid if you have dietary restrictions.

Other Medicines and Supplements. Calcium antacids may interact with other medicines and supplements. Before taking calcium 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. 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 a calcium antacid while you are pregnant or trying to get pregnant.

Breastfeeding. Calcium from calcium antacids passes into breast milk. 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 a calcium antacid while breastfeeding.

Interactions

Do calcium antacids interact with foods or drinks?

There are no known interactions between calcium antacids and foods or drinks.

It is unknown if drinking alcohol will affect calcium antacids.

Do calcium 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.

In particular, make sure that you discuss if you are using any of the following before taking calcium antacids.

  • Bictegravir (found in Biktarvy), dolutegravir (found in Tivicay, Dovato, and others), elvitegravir (found in Genvoya or Stribild), or raltegravir (Isentress), which are medicines used for HIV
  • A thyroid medicine, such as levothyroxine, which is used to raise thyroid hormone levels
  • Lithium, which is a medicine for certain mental health conditions
  • A fluoroquinolone, such as ciprofloxacin (Cipro, Cipro XR, Porquin), levofloxacin, moxifloxacin, or ofloxacin, which is a medicine used to treat certain infections 
  • A bisphosphonate, such as alendronate (Binosto, Fosamax), ibandronate, or risedronate (Actonel, Atelvia), which is a medicine commonly used for osteoporosis
  • A tetracycline, such as doxycycline, minocycline, omadacycline (Nuzyra), sarecycline (Seysara), or tetracycline, which is a medicine used to treat infections or other conditions
  • Digoxin (Lanoxin), which is a medicine used to treat irregular heartbeat and some types of heart failure

Calcium antacids may affect the absorption of many other medicines. Tell your health care provider about all medicines that you take or have recently taken.

This may not be a complete list of medicines that can interact with calcium antacids. Always check with your health care provider.

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 calcium antacids?

If you or someone else has taken too much calcium 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 calcium antacids?

Calcium antacids are meant to be taken only when needed. Take them according to the product instructions or as your health care provider recommends. Do not take double or extra doses.