Sodium Bicarbonate Injection

Sodium bicarbonate is a systemic alkalinizing agent. It most often is administered IV in the treatment of metabolic and respiratory acidosis. Sodium bicarbonate is also used in the acute treatment of hyperkalemia, although it should be kept in mind that this represents palliative treatment for this condition. Sodium bicarbonate is sometimes used for urinary alkalinization. Despite being a highly effective antacid, sodium bicarbonate is rarely used for the chronic treatment of peptic ulcer disease because it can be absorbed and can affect systemic acid-base balance. Sodium bicarbonate was in use prior to 1938 and approved by the FDA at its inception.

Mechanism of Action: After oral administration, sodium bicarbonate neutralizes hydrochloric acid in the stomach, forming sodium chloride, carbon dioxide, and water. Excess bicarbonate ions are absorbed in the small intestine. Thus, all of a dose of exogenous sodium bicarbonate eventually reaches the extracellular fluid, and a mild alkalosis can result. This usually is corrected quickly by the renal system in patients with normal renal function. After IV administration, sodium bicarbonate dissociates to bicarbonate ions, which constitute the conjugate base portion of the body’s extracellular buffer system (bicarbonate/carbonic acid buffer). Administration of sodium bicarbonate will restore acid-base balance in patients with metabolic or respiratory acidosis; however, metabolic alkalosis can result from the use of sodium bicarbonate.

Excess bicarbonate ions that result from the administration of sodium bicarbonate are excreted in the urine, alkalizing the urine. This alkalization decreases renal absorption and increases the clearance of certain drugs, intoxicants, weak acids, and blood pigments.

Mechanism of Action: After oral administration, sodium bicarbonate neutralizes hydrochloric acid in the stomach, forming sodium chloride, carbon dioxide, and water. Excess bicarbonate ions are absorbed in the small intestine. Thus, all of a dose of exogenous sodium bicarbonate eventually reaches the extracellular fluid, and a mild alkalosis can result. This usually is corrected quickly by the renal system in patients with normal renal function. After IV administration, sodium bicarbonate dissociates to bicarbonate ions, which constitute the conjugate base portion of the body’s extracellular buffer system (bicarbonate/carbonic acid buffer). Administration of sodium bicarbonate will restore acid-base balance in patients with metabolic or respiratory acidosis; however, metabolic alkalosis can result from the use of sodium bicarbonate.

Excess bicarbonate ions that result from the administration of sodium bicarbonate are excreted in the urine, alkalizing the urine. This alkalization decreases renal absorption and increases the clearance of certain drugs, intoxicants, weak acids, and blood pigments.

In patients with nonlife-threatening metabolic acidosis, the desired dose of sodium bicarbonate should not be administered as a single, IV injection. Administration over 8 hours via IV infusion or oral administration is preferable.

Long-term administration of bicarbonate with calcium or milk can cause the milk-alkali syndrome, which is manifested by hypercalcemia, metabolic acidosis, renal insufficiency, mental confusion, anorexia, nausea, vomiting, and headache. Patients with a salt-losing nephropathy are at an increased risk of developing the milk-alkali syndrome, so sodium bicarbonate should be used extremely cautiously in these patients. Although patients with renal failure often develop metabolic acidosis and sodium bicarbonate is often used for this condition, the increased sodium load could be detrimental in these patients.

Sodium bicarbonate injection should be administered to children with caution. Parenteral formulations are hypertonic and should be diluted before injection.

Sodium bicarbonate is contraindicated for use in patients with preexisting metabolic alkalosis. Sodium bicarbonate is contraindicated in patients with hypochloremic alkalosis secondary to vomiting, diuretics, or nasogastric suction. The acid-base status of a patient should be assessed periodically during sodium bicarbonate administration to minimize the possibility of overdosage or metabolic alkalosis. Other causes of metabolic alkalosis include Cushing’s syndrome, primary hyperaldosteronism, and Bartter’s syndrome, so sodium bicarbonate should be used cautiously in patients with these conditions.

Sodium bicarbonate therapy should be used cautiously in patients with preexisting respiratory acidosis. Although sodium bicarbonate may successfully correct the acidosis associated with respiratory insufficiency, hypercapnia can worsen. It is important that patients be able to handle the excess carbon dioxide load as a result of sodium bicarbonate administration. Because sodium bicarbonate can worsen preexisting respiratory alkalosis, it should not be used in patients with this condition.

Sodium bicarbonate therapy should be used cautiously in patients with preexisting hypokalemia. Alkalosis can increase the risk of developing arrhythmias in these patients due to a rapid shift of potassium ions from the extracellular space into the intracellular space. Sodium bicarbonate therapy can worsen hypokalemia. In some patients, sodium bicarbonate is used to treat hyperkalemia.

Sodium bicarbonate should not be used for prolonged therapy because of the risk of causing hypernatremia. Rapid injection of hypertonic sodium bicarbonate can cause hypernatremia in neonates, infants, and children under the age of 2; the drug should be administered cautiously to these patients. Sodium bicarbonate therapy should be used with caution in patients receiving corticotropin or corticosteroids, in patients with renal disease or insufficiency, or in patients with congestive heart failure or other condition in which sodium retention could be detrimental.

Sodium bicarbonate is contraindicated in patients with hypocalcemia because of the risk of developing alkalosis-induced tetany.

Sodium bicarbonate pharmaceutical products (e.g., oral tablets, injectable solution) are classified as FDA pregnancy risk category C. Although no untoward effects have been observed in humans, chronic use sodium bicarbonate may lead to systemic alkalosis, which may threaten maternal-fetal health. Increased sodium intake can produce edema and weight increase from fluid retention. The American Gastroenterological Association considers sodium bicarbonate-containing antacids unsafe in pregnancy; there are many other antacids, such as occasional use of calcium carbonate, that are considered appropriate for occasional use for dyspepsia.^[1] Sodium bicarbonate may be used parenterally when critical for the health of the mother. Due to radiographic use, Baros effervescent granules for imaging studies would not be indicated in pregnancy.

Sodium bicarbonate has no specific precautions for use in breast-feeding women. The American Gastroenterological Association states that sodium bicarbonate antacids represent a low risk to the infant when used during breast-feeding.^[1] Chronic or indiscriminate use may result in metabolic alkalosis or sodium and fluid retention in the mother. In general there are other antacids (e.g., calcium carbonate, magnesium hydroxide) that are generally preferred for antacid use due to wider safety margins. Consider the benefits of breast-feeding, the risk of potential infant drug exposure, and the risk of an untreated or inadequately treated condition. If a breast-feeding infant experiences an adverse effect related to a maternally administered drug, healthcare providers are encouraged to report the adverse effect to the FDA.

Overdosage of IV sodium bicarbonate can result in metabolic alkalosis and/or hypernatremia. Metabolic alkalosis is a greater risk in patients with impaired renal function, and the reaction is accompanied by hyperirritability or tetany. The rapid administration of sodium bicarbonate to patients with ketoacidosis can result in clouding of consciousness, obtundation, tremor, seizures, cerebral dysfunction, and lactic acidosis.^[2]

Extravasation of hypertonic solutions of sodium bicarbonate can cause an injection site reaction manifested as tissue necrosis, sloughing, and ulceration. Extravasation may be treated with warm compresses and local injection of lidocaine or hyaluronidase into the affected area.^[2]

Sodium and fluid retention can occur in patients receiving sodium bicarbonate therapy and is especially likely when large doses are administered or when the patient has renal impairment. Sodium bicarbonate-induced peripheral edema can exacerbate heart failure.^[2]

Sodium bicarbonate pharmaceutical products (e.g., oral tablets, injectable solution) are classified as FDA pregnancy risk category C. Although no untoward effects have been observed in humans, chronic use sodium bicarbonate may lead to systemic alkalosis, which may threaten maternal-fetal health. Increased sodium intake can produce edema and weight increase from fluid retention. The American Gastroenterological Association considers sodium bicarbonate-containing antacids unsafe in pregnancy; there are many other antacids, such as occasional use of calcium carbonate, that are considered appropriate for occasional use for dyspepsia.^[1] Sodium bicarbonate may be used parenterally when critical for the health of the mother. Due to radiographic use, Baros effervescent granules for imaging studies would not be indicated in pregnancy.

Sodium bicarbonate has no specific precautions for use in breastfeeding women. The American Gastroenterological Association states that sodium bicarbonate antacids represent a low risk to the infant when used during breastfeeding.^[1] Chronic or indiscriminate use may result in metabolic alkalosis or sodium and fluid retention in the mother. In general, there are other antacids (e.g., calcium carbonate, magnesium hydroxide) that are generally preferred for antacid use due to wider safety margins. Consider the benefits of breastfeeding, the risk of potential infant drug exposure, and the risk of an untreated or inadequately treated condition. If a breastfeeding infant experiences an adverse effect related to a maternally administered drug, healthcare providers are encouraged to report the adverse effect to the FDA.

Store this medication at 68°F to 77°F (20°C to 25°C) and away from heat, moisture and light. Keep all medicine out of the reach of children. Throw away any unused medicine after the beyond-use date. Do not flush unused medications or pour down a sink or drain.

1. Mahadevan U, Kane S. American Gastroenterological Association Institute technical review on the use of gastrointestinal medications in pregnancy. Gastroenterology 2006;131:283-311.
2. Sodium bicarbonate package insert. Lake Forest, IL: Hospira Inc; 2012 October.