Sodium bicarbonate - Drug Monograph

Sodium Bodium Bicarbonate - Drug Monograph

Introduction

Sodium bicarbonate (NaHCO₃), commonly known as baking soda, is an alkalinizing agent with multiple medical applications. It is an essential medication used in various clinical settings, primarily for managing metabolic acidosis and as a urinary alkalinizer. This inorganic salt has been used medically for over a century and remains a critical component of emergency and critical care medicine.

Mechanism of Action

Sodium bicarbonate acts as a systemic alkalinizing agent by increasing plasma bicarbonate levels, which buffers excess hydrogen ion concentration and raises blood pH. The bicarbonate ion combines with hydrogen ions to form carbonic acid, which dissociates into water and carbon dioxide. The carbon dioxide is then eliminated via pulmonary ventilation. This mechanism effectively corrects acid-base imbalances in metabolic acidosis.

Indications

FDA-approved indications:

• Treatment of metabolic acidosis
• Urinary alkalinization
• Management of certain drug intoxications (salicylates, barbiturates)
• Cardiac arrest (as adjunctive therapy)

Off-label uses:

• Prevention of contrast-induced nephropathy
• Treatment of hyperuricemia
• Management of rhabdomyolysis
• Prevention of cisplatin nephrotoxicity

Dosage and Administration

• IV: 2-5 mEq/kg administered over 4-8 hours
• Monitor arterial blood gases to guide therapy

• IV: 1 mEq/kg initially, then 0.5 mEq/kg every 10 minutes
• Use only in prolonged arrest or with pre-existing metabolic acidosis

• Oral: 325 mg to 2 g, 1-4 times daily
• Adjust dose to maintain urine pH between 6.0-7.0

• Renal impairment: Use with caution; monitor electrolytes closely
• Elderly: Reduced doses may be necessary
• Pediatrics: 1-2 mEq/kg IV slowly

Pharmacokinetics

Contraindications

• Hypocalcemia
• Metabolic alkalosis
• Hypokalemia
• Severe pulmonary edema
• Acute pancreatitis (relative contraindication)
• Patients on sodium-restricted diets

Warnings and Precautions

• Risk of metabolic alkalosis with excessive use
• May cause sodium overload leading to edema and heart failure
• Can precipitate hypokalemia and hypocalcemia
• Extravasation may cause tissue necrosis
• Use caution in patients with renal impairment
• Rapid administration may cause hypercapnia and paradoxical CSF acidosis

Drug Interactions

• Lithium: Increased renal lithium excretion
• Amphetamines: Decreased renal elimination
• Quinolones: Reduced solubility may cause crystalluria
• Salicylates: Increased renal elimination
• Mexiletine: Increased renal excretion
• Ephedrine: Decreased renal elimination
• Flecainide: Reduced renal clearance

Adverse Effects

• Metabolic alkalosis
• Edema
• Hypernatremia
• Hypokalemia
• Hypocalcemia
• Nausea/vomiting (oral)

• Tetany (due to hypocalcemia)
• Congestive heart failure
• Intracranial hemorrhage (in neonates)
• Paradoxical intracellular acidosis
• Tissue necrosis with extravasation

Monitoring Parameters

• Arterial blood gases (pH, pCO₂, bicarbonate)
• Serum electrolytes (sodium, potassium, calcium)
• Renal function tests
• Fluid balance and body weight
• Urine pH (for alkalinization therapy)
• ECG monitoring (for potassium changes)
• Neurological status

Patient Education

• Take oral doses with plenty of water
• Report signs of edema, shortness of breath, or muscle twitching
• Avoid excessive antacid use without medical supervision
• Inform all healthcare providers about sodium bicarbonate use
• Store at room temperature away from moisture
• Do not use for prolonged periods without medical supervision
• Be aware of sodium content if on salt-restricted diet

References

1. FDA Prescribing Information for Sodium Bicarbonate Injection 2. Brunton LL, et al. Goodman & Gilman's The Pharmacological Basis of Therapeutics. 13th ed. 3. Lexicomp Online®. Sodium Bicarbonate monograph 4. Clinical Pharmacology [Internet]. Tampa (FL): Elsevier 5. KDIGO Clinical Practice Guideline for Acute Kidney Injury (2012) 6. American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care (2020) 7. Micromedex® Healthcare Series [Internet]. Truven Health Analytics 8. UpToDate®: Sodium bicarbonate: Drug information (2023) 9. Martindale: The Complete Drug Reference. 38th ed. 10. National Library of Medicine Drug Information Portal: Sodium Bicarbonate