What are the indicated uses for sodium bicarbonate (NaHCO3) tablets?

Indicated Uses for Sodium Bicarbonate Tablets

Sodium bicarbonate tablets are primarily indicated for acid neutralization in conditions such as heartburn, acid indigestion, and sour stomach, with specific clinical applications in metabolic acidosis, tricyclic antidepressant overdose, and hyperkalemia when administered under medical supervision. 1, 2

Primary Indications

• Acid neutralization (OTC use)
  • Heartburn
  • Acid indigestion
  • Sour stomach

Medical/Clinical Indications

Metabolic Acidosis

• Indicated in severe metabolic acidosis (pH < 7.0) 1, 3
• Reserved for specific clinical scenarios rather than routine use
• Particularly useful in:
  • Renal tubular acidosis
  • Diarrhea-induced bicarbonate loss

Toxicology

• Tricyclic antidepressant overdose: First-line therapy for sodium channel blocker toxicity 4, 1
  • Initial dose: 1-2 mEq/kg IV
  • Mechanism: Sodium loading plus increased serum pH has additive beneficial effect in treating cardiotoxicity
  • Helps reverse QRS prolongation and hypotension

Electrolyte Abnormalities

• Hyperkalemia: Aids in shifting potassium into cells 4, 1
• Myoglobinuria: Alkalinizes urine to prevent acute kidney injury 4

Malignant Hyperthermia

• Recommended for acidosis management in malignant hyperthermia 4
• Helps with reuptake of potassium ions into cells
• Alkalinizes urine to prevent myoglobin precipitation

Administration Guidelines

• OTC use: 1 tablet dissolved in water as needed 2

  • Maximum daily dose:
    • Adults up to 60 years: 24 tablets/24 hours
    • Adults 60+ years: 12 tablets/24 hours
  • Do not exceed maximum dosage for more than 2 weeks without medical supervision

• Clinical use:

  • Initial IV dose: 1-2 mEq/kg for metabolic acidosis 1
  • Titrate to effect based on pH and clinical response

Important Precautions

• Contraindications:

  • Sodium-restricted diets (unless directed by physician) 2
  • Mixed acidosis with high PaCO2 (may worsen respiratory component) 5

• Monitoring requirements:

  • Serum electrolytes (especially potassium, sodium, calcium)
  • Arterial blood gases
  • ECG (especially with hyperkalemia)
  • Mental status

Potential Adverse Effects

• Hypernatremia (avoid sodium levels >150-155 mEq/L) 1
• Hypocalcemia (ionized)
• Hypokalemia
• Paradoxical intracellular acidosis
• QTc interval prolongation
• Fluid overload in heart failure patients 1, 6

Clinical Pearls

• In hypernatremia, consider THAM (tromethamine) as an alternative alkalinizing agent 1, 5
• For diabetic ketoacidosis, bicarbonate is generally not recommended unless pH < 7.0 1
• Sodium bicarbonate may worsen outcomes in lactic acidosis with pH > 7.15 4
• Recent evidence suggests a small mortality benefit (1.9% absolute reduction) in ICU patients with metabolic acidosis 7
• Always dissolve tablets completely in water before ingestion to avoid serious gastrointestinal injury 2

Remember that while sodium bicarbonate has specific indicated uses, its administration should be guided by clinical parameters and laboratory values rather than simply treating numbers on a blood gas report.