What is the recommended oral dose of sodium bicarbonate (NaHCO3) for antacid use?

Oral Sodium Bicarbonate Dosing for Antacid Use

For antacid use, the FDA-approved dose is 1 tablet (typically 325 mg or 650 mg) dissolved in a glass of water as needed, with a maximum of 24 tablets daily for adults under 60 years and 12 tablets daily for adults 60 years and older. 1

FDA-Approved Antacid Dosing

• Adults under 60 years: Take 1 tablet dissolved completely in water as needed, not exceeding 24 tablets per day 1
• Adults 60 years and older: Take 1 tablet dissolved completely in water as needed, not exceeding 12 tablets per day 1
• Children: Not recommended for antacid use 1

Critical Administration Requirements

• The tablet must be dissolved completely in water before drinking—do not swallow tablets whole for antacid purposes 1
• This dosing is specifically for symptomatic relief of acid indigestion and heartburn, not for treatment of metabolic acidosis 1

Important Safety Considerations

Common pitfall: Patients often exceed recommended doses when self-treating indigestion. Research demonstrates that people frequently select doses far exceeding the recommended half-teaspoon (approximately 2 grams), with some choosing amounts that generate several hundred milliliters of gas within 3 minutes 2. This excessive dosing, particularly when the stomach is already distended, has been implicated in cases of spontaneous gastric rupture 2.

• Rapid gas production from the bicarbonate-acid reaction occurs primarily when large doses are ingested, as CO2 release is normally slow due to dissolution in gastric fluid 2
• The presence of food or alcohol does not significantly affect gas release rates 2

Alternative Formulations for Chronic Use

For patients requiring chronic sodium bicarbonate therapy (such as those with chronic kidney disease or renal tubular acidosis), different formulations and dosing apply:

• Chronic metabolic acidosis: 2-4 grams daily (25-50 mEq/day) in divided doses to maintain serum bicarbonate ≥22 mmol/L 3, 4
• Grocery store baking soda (Arm & Hammer) dissolved in water provides a cost-effective alternative to pharmacy-compounded solutions for chronic therapy, with consistent sodium bicarbonate content 5
• Enteric-coated formulations and soft capsule preparations show different release profiles, with soft capsules releasing less drug at low pH and potentially causing fewer adverse effects 6

When Antacid Dosing Is Inappropriate

Do not use antacid doses for:

• Severe metabolic acidosis (pH <7.1), which requires intravenous administration of 1-2 mEq/kg 3, 4, 7
• Life-threatening toxicological emergencies requiring 50-150 mEq IV boluses 3, 4
• Chronic kidney disease requiring sustained alkalinization 3, 4