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H2 antagonists oral tablet, chewable (800 mg-10 mg-165 mg)

Calcium carbonate, famotidine, and magnesium hydroxide

Generic name: calcium carbonate, famotidine, and magnesium hydroxide

Brand names: Dual Action Complete, Duo Fusion, Pepcid Complete

Used for heartburn
Last updated November 1, 2026 0 views
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What is calcium carbonate, famotidine, and magnesium hydroxide?

Famotidine is a histamine-2 blocker that reduces the amount of acid produced in the stomach. Calcium and magnesium are natural minerals that help neutralize stomach acid.

Calcium carbonate, famotidine, and magnesium hydroxide is a combination medicine used to relieve heartburn caused by acid indigestion and sour stomach.

Calcium carbonate, famotidine, and magnesium hydroxide may also be used for other reasons not mentioned in this medication guide.

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How should I take calcium carbonate, famotidine, and magnesium hydroxide?

Use exactly as directed on the label, or as prescribed by your doctor.

You must chew the chewable tablet before you swallow it.

Do not use more than two tablets in 24 hours.

Call your doctor if your symptoms do not improve after 14 days, or if you have ongoing stomach pain. You may have a more serious stomach condition.

In addition to taking this medication, other tips for managing heartburn include:

  • Do not lie flat or bend over soon after eating.
  • Do not eat late at night, or just before bedtime.
  • Eat slowly and do not eat big meals.
  • If you smoke, quit smoking.
  • If you are overweight, lose weight.
  • Raise the head of your bed.
  • Wear loose fitting clothing around your stomach.

Store at room temperature away from moisture and heat.

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Warnings

You should not use this medicine if you are allergic to famotidine or similar stomach acid reducers, such as ranitidine, cimetidine, Zantac, or Tagamet.

Do not use this medicine if you have trouble swallowing food, if you are vomiting blood, or if you have bloody or tarry stools.

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Before taking this medicine

Heartburn can feel like the early signs of a heart attack. Seek emergency medical help if you experience chest pain that spreads to your jaw or shoulder and you feel anxious or light-headed.

You should not use this medicine if you are allergic to famotidine or similar stomach acid reducers, such as ranitidine, cimetidine, Zantac, Tagamet, and others.

Do not use calcium carbonate, famotidine, and magnesium hydroxide if you have:

  • trouble swallowing food, or pain when swallowing;
  • vomiting with blood; or
  • black, bloody, or tarry stools.

Ask a doctor or pharmacist if this medicine is safe for you to use if you have ever had:

  • wheezing or trouble breathing when you have heartburn;
  • nausea, vomiting, or stomach pain;
  • unusual weight loss;
  • kidney disease; or
  • if you have had heartburn for longer than 3 months.

This medicine may contain phenylalanine. Check the medication label if you have phenylketonuria (PKU).

Ask a doctor before using this medicine if you are pregnant or breastfeeding.

Do not give this medicine to a child younger than 12 years old without medical advice.

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calcium carbonate, famotidine, and magnesium hydroxide side effects

Get emergency medical help if you have signs of an allergic reaction: hives; trouble breathing; swelling of your face, lips, tongue, or throat.

Stop using calcium carbonate, famotidine, and magnesium hydroxide and call your doctor right away if:

  • your heartburn gets worse; or
  • you still have heartburn after 2 weeks of taking calcium carbonate, famotidine, and magnesium hydroxide.

Less serious side effects might happen more often, and you may not have any at all.

This is not a complete list of side effects, and others may happen. Call your doctor for medical advice about side effects. You can report side effects to the FDA at 1-800-FDA-1088.

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Calcium carbonate, famotidine, and magnesium hydroxide dosing information

Usual Adult Dose for Dyspepsia:

Calcium carbonate 800 mg-famotidine 10 mg-magnesium hydroxide 165 mg orally once a day as needed for symptom relief-Maximum dose: Calcium carbonate 1600 mg-famotidine 20 mg-magnesium hydroxide 330 mg/day-Duration of therapy: Up to 14 daysComment: Tablets should be completely chewed prior to swallowing.Use: Relief of heartburn associated with acid indigestion and sour stomach

Usual Pediatric Dose for Dyspepsia:

12 years and older:Calcium carbonate 800 mg-famotidine 10 mg-magnesium hydroxide 165 mg orally once a day as needed for symptom relief-Maximum dose: Calcium carbonate 1600 mg-famotidine 20 mg-magnesium hydroxide 330 mg/day-Duration of therapy: Up to 14 daysComment: Tablets should be completely chewed prior to swallowing.Use: Relief of heartburn associated with acid indigestion and sour stomach

What happens if I miss a dose?

Since calcium carbonate, famotidine, and magnesium hydroxide is taken as needed, you might not have a regular dosing schedule. If you miss a dose and it’s almost time for your next one, just skip the missed dose. Do not take two doses at the same time.

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What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Overdose symptoms may include nausea, vomiting, diarrhea, stomach pain, fast heart rate, or fainting.

Do not take this medicine together with regular famotidine (Pepcid, Pepcid AC, Pepcid RPD) or with other stomach acid reducers.

Avoid foods or drinks that are more likely to cause heartburn, such as chocolate, caffeine, alcohol, some fruits and vegetables, and rich, spicy, fatty, or fried foods.

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What other drugs will affect calcium carbonate, famotidine, and magnesium hydroxide?

Calcium carbonate, famotidine, and magnesium hydroxide can make it harder for your body to absorb other medicines you take by mouth. Ask a doctor or pharmacist before using calcium carbonate, famotidine, and magnesium hydroxide with any other medications.

Other drugs may affect calcium carbonate, famotidine, and magnesium hydroxide, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using.

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Related medicines

Before you take this medicine: the information on this page is general and may not cover your personal circumstances. Read the label supplied with your medicine and ask a pharmacist or doctor if you are unsure, especially if you are pregnant, breastfeeding, taking other medicines or managing a long-term condition.
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