Sodium hydrogen carbonate: clinical use

Prescribing considerations

• Select the formulation by indication; oral products are not interchangeable with concentrated intravenous preparations.
• Assess total medicinal and dietary sodium, especially with chronic use, hypertension, heart failure, oedema, renal impairment, cirrhosis or pre-eclampsia.
• Treat the underlying cause of metabolic acidosis and ensure adequate ventilation and perfusion; bicarbonate can increase carbon dioxide production.
• Routine neonatal resuscitation use is not supported; the selected injection is reserved for specified prolonged emergencies after ventilation and circulation are established.
• Reassess persistent dyspepsia because sodium hydrogen carbonate can mask symptoms of ulceration or gastric malignancy.

Contraindications and cautions

• Hypersensitivity to the active substance or product excipients; gastro-resistant capsules are contraindicated with soya or peanut hypersensitivity.
• Metabolic or respiratory alkalosis.
• Product-dependent restrictions include hypernatraemia, hypokalaemia, hypocalcaemia, chloride depletion, hypochlorhydria and conditions requiring sodium restriction.
• Age restrictions differ between oral products; check the product-specific licence.

Monitoring

• Acid–base status and serum bicarbonate.
• Sodium, potassium, calcium and chloride concentrations.
• Blood gases, ventilation and carbon dioxide during intravenous treatment.
• Fluid balance, blood pressure and signs of oedema or pulmonary congestion.
• Urine pH, acid–base status and electrolytes when alkalinising urine.
• Administration site and vascular access during concentrated intravenous treatment.

Clinical pharmacology

Bicarbonate is a physiological extracellular buffer. It neutralises acid, increases plasma bicarbonate and pH, and is converted with hydrogen ions to carbonic acid, then carbon dioxide and water. Renal bicarbonate excretion raises urinary pH and changes the clearance of weak acids and bases.

Formulation and product differences

• Standard 500 mg hard capsules act after gastrointestinal dissolution and may produce carbon dioxide in the stomach.
• Nephrotrans 500 mg soft gastro-resistant capsules release in the small intestine, reducing gastric carbon dioxide formation; they contain soya oil, sorbitol and propylene glycol.
• The 84 mg/ml oral solution is measured with a supplied graduated oral syringe.
• Sodium Bicarbonate BP is a 100% powder or granule product licensed for oral antacid use and external application.
• The 8.4% injection is supplied in ampoules for slow intravenous administration in selected emergencies.
• The 8.4% infusion is hypertonic and specified for central venous infusion.

Solution for infusion

Route: Intravenous

Strengths: 8.4% w/v

Capsule

Route: Oral

Strengths: 500 mg

Gastro-resistant capsule

Route: Oral

Strengths: 500 mg

Oral solution

Route: Oral

Strengths: 84 mg/mL