Intravenous sodium bicarbonate (Meylon) for severe metabolic acidosis
Intravenous sodium bicarbonate is administered to increase plasma bicarbonate and raise blood pH in metabolic acidosis while the underlying cause is treated [1]. The dose is individualized using acid-base status when available, or calculated from base excess to target bicarbonate replacement [1], [2].
Administration and preparation
Sodium bicarbonate injection is administered intravenously [1].
IV bolus dosing
For older children and adults receiving bicarbonate for metabolic acidosis, an IV bolus dose of approximately 1 mEq/kg may be given, with repeat dosing based on arterial blood gas measurements [2].
IV dosing by total bicarbonate replacement
For metabolic acidosis, the amount of bicarbonate to be given over 4 to 8 hours in older children and adults is approximately 2 to 5 mEq/kg based on severity judged by total CO2 content, blood pH, and clinical condition [1], [2].
Base-excess–guided calculated dosing
When blood gases are used to guide therapy, the bicarbonate dose can be calculated from negative base excess and body weight using the product labeling approach [1]. The calculated dose may be initiated at one-half the calculated amount, with continuation adjusted after repeat blood gas assessment [1].
Infusion dosing (rate and typical concentration approach)
Continuous infusion regimens used in practice include administration of bicarbonate diluted in IV fluids, with subsequent dosing titrated to acid-base response and repeat blood gases [1], [3]. Example infusion practice described in reference dosing summaries includes 150 mEq in 1 L of D5W infused at about 1 to 1.5 L/hour during the first hour for metabolic acidosis [3].
Monitoring during therapy
Arterial blood gas and serum bicarbonate should be monitored during therapy to guide repeat boluses and titration of infusions [1], [2], [3]. Serum sodium should be monitored because sodium bicarbonate therapy can increase sodium load and worsen hypernatremia risk [4].
Safety considerations and common contraindications to account for
Sodium bicarbonate therapy can cause metabolic alkalosis and hypernatremia if overdosed or not appropriately titrated [4]. Respiratory and metabolic alkalosis and conditions where sodium administration is contraindicated (for example, severe cardiac insufficiency, edema, and hypertension) are listed as situations to avoid sodium bicarbonate use [5].
Practical dosing workflow for severe metabolic acidosis
A bicarbonate dose should be calculated using the patient’s acid-base status (negative base excess when available) or selected using weight-based dosing with subsequent reassessment using arterial blood gases [1], [2]. Repeat dosing should be guided by blood gas response rather than fixed empiric dosing [1], [2].