Gaviscon - Drug Monograph

Introduction

Gaviscon is an over-the-counter antacid medication primarily used for symptomatic relief of gastroesophageal reflux disease (GERD), heartburn, and acid indigestion. Unlike systemic antacids, Gaviscon forms a protective foam barrier that floats on stomach contents, providing localized relief. It is available in various formulations including liquid suspensions, chewable tablets, and dual-action formulas.

Mechanism of Action

Gaviscon contains two primary active ingredients: sodium alginate and either sodium bicarbonate or calcium carbonate. When ingested, sodium bicarbonate reacts with gastric acid to produce carbon dioxide, which causes the alginate to precipitate into a gel. This gel forms a low-density foam barrier that floats on top of gastric contents, physically preventing reflux into the esophagus. The antacid components (calcium carbonate or sodium bicarbonate) additionally neutralize gastric acid, providing immediate symptomatic relief.

Indications

• Symptomatic relief of gastroesophageal reflux disease (GERD)
• Heartburn and acid regurgitation
• Dyspepsia with acid-related symptoms
• Postprandial heartburn
• Relief of symptoms associated with reflux esophagitis

Dosage and Administration

• Chewable tablets: 2-4 tablets after meals and at bedtime (maximum 16 tablets/24 hours)
• Liquid formulations: 10-20 mL after meals and at bedtime (maximum 80 mL/24 hours)

• Chew tablets thoroughly before swallowing
• Shake liquid formulations well before use
• Administer after meals and at bedtime
• Do not take with other medications (separate by at least 2 hours)

• Renal impairment: Use with caution due to sodium content
• Elderly: Standard adult dosing
• Pediatrics: Not recommended for children under 12 unless directed by physician

Pharmacokinetics

Contraindications

• Hypersensitivity to any component of the formulation
• Severe renal impairment (for sodium-containing formulations)
• Hypercalcemia (for calcium carbonate-containing formulations)
• Hypophosphatemia
• Patients on sodium-restricted diets (for high-sodium formulations)

Warnings and Precautions

• Contains sodium: Use caution in patients with hypertension, heart failure, or renal impairment
• Calcium-containing formulations: Risk of milk-alkali syndrome with prolonged high-dose use
• May alter absorption of other medications
• Not for prolonged use without medical supervision (beyond 2 weeks)
• Use in pregnancy: Generally considered safe but consult healthcare provider
• Use in nursing mothers: Components not expected to be excreted in breast milk

Drug Interactions

• Tetracyclines: Reduced absorption (separate administration by至少 2 hours)
• Fluoroquinolones: Reduced absorption (separate administration by至少 2 hours)
• Iron supplements: Reduced absorption
• Thyroid hormones: Reduced absorption
• Digoxin: Altered absorption possible
• Ketoconazole/Itraconazole: Reduced absorption due to pH alteration
• Phosphate supplements: Calcium carbonate may bind phosphate

Adverse Effects

• Constipation (calcium-containing formulations)
• Diarrhea (magnesium-containing formulations in some formulations)
• Flatulence
• Chalky taste

• Milk-alkali syndrome (with prolonged high-dose calcium carbonate use)
• Electrolyte imbalances
• Allergic reactions

Monitoring Parameters

• Symptom relief and frequency of use
• Electrolytes in prolonged use (especially sodium, calcium)
• Renal function in patients with pre-existing renal impairment
• Signs of fluid overload in sodium-sensitive patients
• Adherence to recommended duration of therapy

Patient Education

• Use as directed for symptomatic relief only
• Do not exceed recommended dosage or duration
• Chew tablets thoroughly and do not swallow whole
• Shake liquid formulations well before each use
• Separate administration from other medications by至少 2 hours
• Consult healthcare provider if symptoms persist beyond 2 weeks
• Report any signs of allergic reaction or worsening symptoms
• Be aware of sodium content if on sodium-restricted diet
• Store at room temperature, away from moisture

References

1. Mandel KG, Daggy BP, Brodie DA, et al. Review article: alginate-raft formulations in the treatment of heartburn and acid reflux. Aliment Pharmacol Ther. 2000;14(6):669-690. 2. Pharmaceutical Journal. Gaviscon: how it works and when to use it. 2021. 3. Micromedex® Healthcare Series. Gaviscon drug monograph. IBM Watson Health. 4. British National Formulary. Alginate-containing antacid preparations. BNF 82. 5. FDA OTC Monograph for Antacid Products. 2021. 6. Kwiatek MA, Roman S, Fareeduddin A, et al. An alginate-antacid formulation (Gaviscon Double Action Liquid) can eliminate the postprandial acid pocket in symptomatic GERD patients. Aliment Pharmacol Ther. 2011;34(1):59-66.