What are sodium bicarbonate tablets used to treat?

Sodium Bicarbonate Tablets: Clinical Uses and Indications

Sodium bicarbonate tablets are primarily used to treat metabolic acidosis, prevent contrast-induced nephropathy, manage hyperkalemia, and neutralize excess acid in conditions such as chronic kidney disease, certain drug overdoses, and severe diarrhea with bicarbonate loss. 1

Primary Clinical Indications

1. Metabolic Acidosis

• Chronic Metabolic Acidosis: Particularly in chronic kidney disease patients
  • Recommended oral dose: 2-4 g/day (25-50 mEq/day) 1
  • Goal: Maintain serum bicarbonate levels at or above 22 mmol/L 1
  • Benefits: Slows the loss of kidney function with aging 2

2. Contrast-Induced Nephropathy Prevention

• Recommended protocol: 3 mL/kg for 1 hour before contrast medium, followed by 1 mL/kg/h for 6 hours after procedure 1

3. Toxicological Emergencies

• Tricyclic Antidepressant Overdose: First-line therapy for life-threatening cardiotoxicity 1
• Aspirin Toxicity: Helps with urinary alkalinization to enhance elimination 3

4. Other Indications

• Hyperkalemia: Helps shift potassium into cells 1, 3
• Severe Diarrhea with Bicarbonate Loss: Replaces lost bicarbonate 1
• Rhabdomyolysis: May help prevent kidney injury 3
• Dyspepsia/Acid Reflux: Over-the-counter use as an antacid 4

Mechanism and Benefits in Chronic Kidney Disease

Sodium bicarbonate supplementation addresses the acid-base imbalance that occurs with:

• Low fruit and vegetable consumption (leading to low alkali intake) 2
• High consumption of animal protein, cereals, and grains (leading to nonvolatile acid production) 2

This imbalance creates a chronic low-grade metabolic acidosis that worsens with age as kidney function declines. Sodium bicarbonate helps by:

• Reducing endothelin 1 excretion 2
• Decreasing net endogenous acid production 2
• Slowing progression of kidney disease 2

Dosing Considerations

• Chronic Acidosis: 2-4 g/day (25-50 mEq/day) orally 1
• Acute Severe Acidosis: 1-2 mEq/kg IV bolus of 8.4% solution 1
• Individualized Dosing: Titrated to maintain serum bicarbonate ≥22 mmol/L 1

Important Precautions and Monitoring

• Not Recommended for Routine Use in Cardiac Arrest: Except in special situations like preexisting metabolic acidosis, hyperkalemia, or tricyclic antidepressant overdose 2, 1
• Not Recommended for pH ≥7.15: To improve hemodynamics or reduce vasopressor requirements 1
• Monitoring Requirements: ECG, blood pressure, serum pH, sodium, potassium, and mental status 1

Potential Adverse Effects

• Metabolic Alkalosis: From excessive administration 4
• Electrolyte Imbalances: Hypernatremia, hypocalcemia, hypokalemia 5
• Fluid Overload: Due to sodium load 3
• Paradoxical Intracellular Acidosis: Can worsen cellular function 3, 5
• Inactivation of Simultaneously Administered Catecholamines: Important drug interaction 1

Clinical Pearls

• In patients with chronic kidney disease, increasing fruit and vegetable intake may be more beneficial than sodium bicarbonate tablets, as this approach also decreases systolic blood pressure and body weight 2
• For patients with hyperkalemia, sodium bicarbonate is particularly useful as it decreases serum potassium levels 5
• In patients with hypernatremia, alternative alkalizing agents like THAM may be preferred as sodium bicarbonate increases serum sodium 5
• Sodium bicarbonate should not be mixed with vasoactive amines or calcium 1

Evidence-Based Outcomes

The BICAR-ICU trial showed that in patients with severe metabolic acidemia, sodium bicarbonate had no overall effect on mortality, but significantly improved survival in the subgroup of patients with acute kidney injury 6, highlighting the importance of patient selection when considering this therapy.