Which is better, famotidine or Gaviscon? A Pharmacological Comparison for Heartburn

October 12, 2025 •

4 min read

According to research published by the National Institutes of Health, while antacids provide rapid relief for acid reflux, they offer a significantly shorter duration of effect compared to H2 blockers like famotidine. The question of which is better, famotidine or Gaviscon, depends on the nature and timing of your symptoms, as their pharmacological actions are fundamentally different.

Quick Summary

Famotidine and Gaviscon treat heartburn differently; Famotidine reduces stomach acid production for prolonged relief, whereas Gaviscon rapidly neutralizes acid and forms a protective barrier for immediate, short-term relief.

Key Points

Different Mechanisms: Famotidine reduces acid production systemically, while Gaviscon neutralizes acid directly and forms a protective physical barrier.
Speed vs. Duration: Gaviscon provides faster, on-demand relief for immediate heartburn, whereas famotidine offers longer-lasting preventative effects.
Best for Occasional Heartburn: Gaviscon is ideal for sporadic episodes, especially after eating, due to its rapid onset and protective barrier.
Best for Frequent Reflux: Famotidine is more suitable for managing persistent, frequent, or nocturnal acid reflux symptoms due to its longer duration of action.
Combined Use: It is possible and sometimes recommended to use both medications, with Gaviscon handling immediate breakthrough symptoms and famotidine providing background prevention.
Check Side Effects: Famotidine may cause headaches or dizziness, while Gaviscon's antacids can cause constipation or diarrhea, depending on their formulation.
Consult a Professional: Always seek medical advice for persistent symptoms or before starting a new treatment regimen, especially when combining medications.

Understanding the Mechanisms: How Famotidine and Gaviscon Work

At first glance, both famotidine and Gaviscon appear to address the same problem: excess stomach acid. However, they accomplish this via entirely different pathways, and understanding these mechanisms is the key to determining which is the best choice for your specific needs.

How Famotidine Works (The H2 Blocker)

Famotidine, the active ingredient in Pepcid AC and other generic brands, belongs to a class of drugs known as H2-receptor antagonists, or H2 blockers. It works systemically by targeting and blocking histamine receptors on the parietal cells of the stomach lining. By blocking these receptors, famotidine effectively reduces the amount of acid the stomach produces. The reduction in acid production is not immediate, but it is long-lasting, with effects sustained for up to 12 hours. Famotidine is therefore considered a preventative medication, best taken proactively to ward off symptoms.

Key actions of famotidine:

Reduces acid production: Blocks the histamine signal that triggers acid release from the stomach's parietal cells.
Provides sustained relief: Works over an extended period, making it suitable for managing frequent or nocturnal heartburn.
Requires time to become fully effective: The full acid-suppressing effect takes several hours to manifest, though some relief can begin sooner.

How Gaviscon Works (The Alginate Raft)

Gaviscon works in two ways, combining the actions of an antacid with a unique foaming agent called sodium alginate. The antacid ingredients, which typically include aluminum hydroxide and magnesium carbonate, work immediately to neutralize existing stomach acid. This provides rapid relief from the burning sensation. The unique part of Gaviscon is its foaming agent, which reacts with stomach acid to form a viscous, foam-like gel, or "raft," that floats on top of the stomach contents. This physical barrier helps to block acid from refluxing back into the esophagus, which is especially beneficial for those who experience reflux after eating or when lying down.

Key actions of Gaviscon:

Neutralizes existing acid: Provides immediate relief from active heartburn symptoms.
Forms a protective barrier: The alginate raft prevents stomach acid from splashing up into the esophagus.
Short-term action: The neutralizing effect is relatively short-lived compared to famotidine, though the alginate barrier can provide more sustained localized relief than a simple antacid.

Onset and Duration: Fast Relief vs. Long-Term Prevention

Choosing between these two medications often comes down to the speed of relief needed versus the duration of that relief.

Onset of Action: Gaviscon's antacid components begin working almost immediately upon ingestion to neutralize acid, making it the clear winner for instant symptom relief. Famotidine has a delayed onset of action, with effects beginning in about 15-60 minutes, and peak acid-reduction occurring later.
Duration of Effect: The effect of a basic antacid is short, often lasting only an hour or two, although Gaviscon's alginate barrier can extend its protective qualities. In contrast, famotidine's acid-reducing effects last for up to 12 hours. This long duration is why famotidine is better for preventing heartburn over a longer period, such as throughout the night.

Comparing Famotidine and Gaviscon: A Side-by-Side View


Feature	Famotidine (H2 Blocker)	Gaviscon (Antacid + Alginate)
Mechanism	Reduces acid production by blocking H2 receptors in the stomach.	Neutralizes existing acid and forms a protective foam barrier (raft) in the stomach.
Best For	Preventing frequent heartburn and nocturnal acid reflux.	Rapid, on-demand relief for immediate heartburn or reflux, especially after a meal.
Onset of Action	Slower, begins working within 15-60 minutes.	Fast, works almost immediately.
Duration of Effect	Long-lasting, up to 12 hours.	Shorter, providing relief for a couple of hours or as long as the alginate raft remains effective.
Common Side Effects	Headache, dizziness, constipation, or diarrhea.	Constipation (aluminum) or diarrhea (magnesium).
Formulations	Tablets, chewable tablets, oral suspension.	Chewable tablets, liquids.

When to Choose Each Medication

Choose Gaviscon for Immediate Heartburn

If you have an occasional episode of heartburn triggered by a specific meal or beverage, and you need quick relief, Gaviscon is the more appropriate choice. Its ability to neutralize existing acid immediately and create a physical barrier is ideal for this scenario. Gaviscon's unique raft-forming action can also be particularly helpful in controlling postprandial (after-meal) esophageal acid exposure.

Choose Famotidine for Persistent or Nighttime Reflux

For individuals experiencing frequent heartburn (two or more times a week) or symptoms that interfere with sleep, famotidine's long-lasting acid-reducing effect is more beneficial. Taking famotidine preventatively, such as before a meal known to cause issues or before bed, can stop the symptoms before they start. It provides a sustained period of low acid production that can manage chronic issues more effectively.

Combining Medications for Comprehensive Relief

It is possible to use both medications in a complementary fashion. An individual with frequent heartburn might take famotidine in the morning to prevent symptoms throughout the day and use Gaviscon for any breakthrough, immediate discomfort. In fact, some products like Pepcid Complete combine famotidine and antacids in a single pill for both fast-acting and long-lasting relief. As with any medication, always follow the dosage instructions and consult a doctor or pharmacist with any questions. Some studies have noted that Gaviscon can have major drug interactions, so be sure to check with your doctor before combining.

Conclusion: Matching the Treatment to the Symptom

Ultimately, there is no single "better" medication. The optimal choice between famotidine and Gaviscon is determined by the specific symptom presentation. Gaviscon is superior for immediate, on-demand relief of occasional heartburn, thanks to its fast-acting neutralization and physical barrier effect. In contrast, famotidine is the better option for long-term prevention and control of frequent or nocturnal acid reflux, due to its prolonged acid-reducing action. A good strategy for those with mixed symptom patterns might involve using both medications at different times of the day. For persistent or severe symptoms, it is always best to consult a healthcare provider to determine the most effective treatment plan.

For more information on managing GERD and acid reflux, you can refer to the Mayo Clinic's guide on Gastroesophageal reflux disease (GERD).

Frequently Asked Questions

Yes, it is generally safe to take both medications concurrently. Gaviscon can provide immediate relief while famotidine works over a longer period. Some products, like Pepcid Complete, even combine famotidine with antacids for both fast and prolonged relief.

Gaviscon works significantly faster. Its antacid components begin neutralizing stomach acid almost immediately upon reaching the stomach, providing very rapid relief from the burning sensation.

Famotidine is typically better for nighttime heartburn because its effects last for up to 12 hours, suppressing acid production throughout the night. Gaviscon's alginate raft can also be beneficial, especially if taken just before bed, as it creates a physical barrier against reflux when lying down.

While Gaviscon can be used daily for short periods, you should not use the maximum dosage for more than two weeks unless directed by a doctor. Prolonged use of antacids can mask underlying conditions or cause electrolyte imbalances.

For prevention, famotidine can be taken 10 to 60 minutes before a meal or beverage that typically causes you heartburn. For treating existing symptoms, it can be taken at the onset of symptoms or as directed by a healthcare provider.

The sodium alginate in Gaviscon forms a viscous, gel-like foam, or "raft," that floats on top of the stomach's contents. This physical barrier prevents stomach acid from splashing up into the esophagus, which is a major cause of heartburn and reflux.

If heartburn persists or worsens, or if you need medication for more than 14 days, you should consult a doctor. This could indicate a more serious condition requiring different treatment, such as a proton pump inhibitor (PPI) or further medical evaluation.