Sign Out
Pharmacology: Pharmacodynamics: Sodium chloride is the principal salt involved in maintaining the osmotic tension of the blood and tissues; changes in osmotic tension influence the movement of fluids and diffusion of salts in cellular tissues.
Solutions containing sodium chloride are extensively used for the prevention or correction of fluid and electrolyte deficits or imbalance in a wide range of clinical situations.
Sodium citrate, after absorption, is metabolized and has actions similar to those of sodium bicarbonate. It neutralizes the acid secretion in the stomach with the liberation of carbon dioxide. After absorption, it is retained by kidneys to meet any deficit of bicarbonate in the plasma, e.g. in metabolic acidosis.
Potassium chloride is mainly used in the prevention and treatment of potassium deficiency. As it contains chloride ions, it is employed in the treatment of hypokalaemia associated with hypochloraemic alkalosis.
Glucose is given by mouth as a readily absorbed carbohydrate in conditions associated with insufficiency of carbohydrates: it provides rapidly with available source of energy. It also reduces the need for the metabolism of fats and thus prevents ketonaemia.
Pharmacokinetics: Sodium chloride is readily absorbed from the gastrointestinal tract. It is present in all body fluids but is mainly found in the extracellular fluid. The amount of sodium chloride normally lost in the sweat is small and the osmotic equilibrium is maintained by the excretion of surplus amounts in the urine.
Potassium salts other than the phosphate, sulphate, and tartrate are generally readily absorbed from the gastrointestinal tract. Potassium is excreted mainly by the distal tubules of the kidney; 5 to 10 mmol a day may be excreted in the faeces, and some in perspiration. The urinary excretion of potassium continues even when intake is low and faecal losses may be large in the presence of diarrhoea.
Glucose is absorbed from the gastrointestinal tract. Three pathways of metabolism are established: glycolysis leading to the formation of pyruvate (aerobic) or lactate (anaerobic), followed by the Krebs tricarboxylic acid cycle (citric acid cycle), leading to metabolism to carbon dioxide and water, a pentose phosphate pathway leads also to carbon dioxide and water. Energy is released in these processes. Glucose is also stored as glycogen in the liver and muscles. Blood-glucose concentrations are maintained on healthy persons within normal limits by the insulin, which facilitates the passage of glucose through cell membranes, and other homeostatic mechanisms. The body can metabolise about 800 mg per kg body weight hourly. Glucose facilitates the absorption of sodium from the intestinal tract.
