About Sodium Bicarbonate Sodium compound, Systemic Antacid ,alkalinizer. Mechanism of Action of Sodium Bicarbonate Sodium bicarbonate in water dissociates to sodium (Na+) and bicarbonate (HCO3 -) ions. Sodium (Na+) is the principal cation of the extracellular fluid and it maintains fluid and electrolyte disturbances. Bicarbonate (HC03 -) is a normal constituent of body fluids. Plasma concentration is regulated by the kidney through acidification of the urine when there is a deficit or by alkalinization of the urine when there is an excess. Bicarbonate anion is considered ``labile`` since at a proper concentration of hydrogen ion (H+) it may be converted to carbonic acid (H2CO3) and hence to its volatile form, carbon dioxide (CO2) which is excreted by the lung. Sodium bicarbonate can neutralize or reduce acids in the blood, or urine. It is also used in emergency medical situations (heart attacks, serious kidney or lung problems) to correct the normal acid-base balance in the blood