On this page · 8 sections

Duo Fusion

Generic name: calcium carbonate, famotidine, and magnesium hydroxide

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

Used for heartburn
Last updated November 2, 2026 0 views
Share

What is Duo Fusion?

Famotidine is a H2 antagonist that reduces the amount of acid the stomach makes. Calcium and magnesium are natural minerals that help neutralize acid in the stomach.

Duo Fusion is a combination medicine used to relieve heartburn caused by acid indigestion and sour stomach.

Duo Fusion may also be used for reasons not mentioned in this medication guide.

This section was rewritten for readability and reviewed for meaning.

How should I take Duo Fusion?

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

You must chew the chewable tablet before swallowing 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.

This section was rewritten for readability and reviewed for meaning.

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.

This section was rewritten for readability and reviewed for meaning.

Before taking this medicine

Heartburn can feel like the early signs of a heart attack. Get emergency medical help if you have 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 Duo Fusion 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 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.

This section was rewritten for readability and reviewed for meaning.

Duo Fusion side effects

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

Stop using Duo Fusion and call your doctor right away if:

  • your heartburn gets worse; or
  • you still have heartburn after 2 weeks of taking Duo Fusion.

Less serious side effects may happen more often, and you may not experience 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 may report side effects to FDA at 1-800-FDA-1088.

This section was rewritten for readability and reviewed for meaning.

What happens if I miss a dose?

Since Duo Fusion is used as needed, you may not have a regular dosing schedule. If you miss a dose and it's almost time for your next dose, skip the missed dose. Do not take two doses at the same time.

This section was rewritten for readability and reviewed for meaning.

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.

This section was rewritten for readability and reviewed for meaning.

What other drugs will affect Duo Fusion?

Duo Fusion can make it harder for your body to absorb other medicines you take by mouth. Ask a doctor or pharmacist before using this medicine with any other medications.

Other drugs may affect Duo Fusion, 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.

This section was rewritten for readability and reviewed for meaning.

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.
General medicine information Consumer-friendly language

Content is provided for education and is not medical advice. See our medical disclaimer.