SODIUM BICARBONATE INJECTION USP

Sodium Bicarbonate Injection USP is indicated in the treatment of metabolic acidosis which may occur in severe renal disease, uncontrolled diabetes, circulatory insufficiency due to shock or severe dehydration, extracorporeal circulation of blood, cardiac arrest and severe primary lactic acidosis.  Sodium bicarbonate is further indicated in the treatment of certain drug intoxications, including barbiturates (where dissociation of the barbiturate-protein complex is desired), in poisoning by salicylates or methyl alcohol and in hemolytic reactions requiring alkalinization of the urine to diminish nephrotoxicity of blood pigments.  Sodium bicarbonate is also indicated in severe diarrhea which is often accompanied by a significant loss of bicarbonate.

Treatment of metabolic acidosis should, if possible, be superimposed on measures designed to control the basic cause of the acidosis - e.g., insulin in uncomplicated diabetes, blood volume restoration in shock.  But since an appreciable time interval may elapse before all of the ancillary effects are brought about, bicarbonate therapy is indicated to minimize risks inherent to the acidosis itself.

Vigorous bicarbonate therapy is required in any form of meta­bolic acidosis where a rapid increase in plasma total CO₂ content is crucial - e.g., cardiac arrest, circulatory insuffi­ciency due to shock or severe dehydration, and in severe primary lactic acidosis or severe diabetic acidosis.

Solutions containing sodium ions should be used with great care, if at all, in patients with congestive heart failure, severe renal insufficiency and in clinical states in which there exists edema with sodium retention.

In patients with diminished renal function, administration of solutions containing sodium ions may result in sodium retention.

The intravenous administration of these solutions can cause fluid and/or solute overloading resulting in dilution of serum electrolyte concentrations, overhydration, congested states or pulmonary edema.

The risk of dilutional states is inversely proportional to the electrolyte concentrations of administered parenteral solutions. The risk of solute overload causing congested states with peripheral and pulmonary edema is directly proportional to the electrolyte concentrations of such solutions.

Additives may be incompatible.  Consult with pharmacist if available. When introducing additives, use aseptic technique, mix thoroughly and do not store.

Extravascular infiltration should be avoided (see ADVERSE REACTIONS).

Overly aggressive therapy with Sodium Bicarbonate Injection USP can result in metabolic alkalosis (associated with muscular twitchings, irritability, and tetany) and hypernatremia.

Inadvertent extravasation of intravenously administered hypertonic solutions of sodium bicarbonate have been reported to cause chemical cellulitis because of their alkalinity, with tissue necrosis, ulceration or sloughing at the site of infiltration. Prompt elevation of the part, warmth and local injection of lidocaine or hyaluronidase are recommended to prevent slough­ing of extravasated i.v. infusions.

Sodium Bicarbonate Injection USP is administered by the intravenous route.

In cardiac arrest, a rapid intravenous dose of 200 to 300 mmol (mEq) of bicarbonate, given as a 7.5% or 8.4% solution, is suggested for adults. Caution should be observed in emergencies where very rapid infusion of large quantities of bicarbonate is indicated. Bicarbonate solutions are hypertonic and may produce an undesirable rise in plasma sodium concentration in the process of correcting the metabolic acidosis. In cardiac arrest, however, the risks from acidosis exceed those of hypernatremia.

In infants (up to two years of age), the 4.2% solution is recom­mended for intravenous administration at a dose not to exceed 8 mmol (mEq)/kg/day. Slow administration rates and the 4.2% solution are recommended in neonates, to guard against the possibility of producing hypernatremia, decreasing cerebrospinal fluid pressure and inducing intracranial hemorrhage.

In less urgent forms of metabolic acidosis, Sodium Bicarbonate Injection USP may be added to other intravenous fluids. The amount of bicarbonate to be given to older children over a four to eight hour period is approximately 2 to 5 mmol (mEq)/kg of body weight - depending upon the severity of the acidosis as judged by the lowering of total CO₂ content, blood pH and clinical condition of the patient.  Bicarbonate therapy should always be planned in a stepwise fashion since the degree of response from a given dose is not precisely predictable.  Initially an infusion of 2 to 5 mmol (mEq)/kg body weight over a period of 4 to 8 hours will produce a measurable improvement in the abnormal acid base status of the blood.  The next step of therapy is dependent upon the clinical response of the patient.  If severe symptoms have abated, then the frequency of administration and the size of the dose may be reduced.

In general, it is unwise to attempt full correction of a low total CO₂ content during the first 24 hours of therapy, since this may be accompanied by an unrecognized alkalosis because of a delay in the readjustment of ventilation to normal. Owing to this lag, the achievement of total CO₂ content of about 20 mmol (mEq)/liter at the end of the first day of therapy will usually be associated with a normal blood pH.  Further modifi­cation of the acidosis to completely normal values usually occurs in the presence of normal kidney function when and if the cause of the acidosis can be controlled. Values for total CO₂, which are brought to normal or above normal within the first day of therapy, are very likely to be associated with grossly alkaline values for blood pH, with ensuing undesired side effects.