Calcium carbonate 碳酸钙 Sodium bicarbonate 碳酸钠 Their pharmacological effect is produced by reacting with HCI to form carbon dioxide and CaCl,(and NaCl in the case of sodium bicarbonate).In doing so,the two drugs reduce HCI in the stomach. Side effects are those caused by excessive CO2(belching, gastric distention).Unreacted alkali can be absorbed and can produce alkalosis.Calcium carbonate 碳酸钙 Their pharmacological effect is produced by reacting with HCl to form carbon dioxide and CaCl2 (and NaCl in the case of sodium bicarbonate). In doing so, the two drugs reduce HCl in the stomach. Side effects are those caused by excessive CO2 (belching, gastric distention). Unreacted alkali can be absorbed and can produce alkalosis. Sodium bicarbonate 碳酸钠