Pharmacological properties : תכונות פרמקולוגיות

Pharmacodynamic Properties

5.1   Pharmacodynamic properties
Pharmacotherapeutic Group:  Solutions affecting the electrolyte balance, electrolytes
ATC-Code:           B05B B01

Mechanism of action
The solution contains the essential ions present in extracellular fluid. Therefore the pharmacodynamic properties of the ions contained in it (sodium, potassium, calcium, chloride, lactate) are the same as in normal physiology.

Lactate is a key substrate in intermediary metabolism. Inter alia, it is oxidised to bicarbonate, exerting a mild alkalinising effect.

Pharmacodynamic effect
Compound Sodium Lactate has a similar electrolyte composition as the extracellular fluid (neglecting some very minor differences). It is used for correction of serum electrolyte and acid-base imbalances. Electrolytes are administered in order to achieve or to maintain a normal osmotic situation in both the extra- and the intracellular space.

Due to its distribution (see below) the solution has a short haemodynamic effect.

On account of the proportion of metabolisable anions Compound Sodium Lactate is particularly indicated in patients with a tendency to acidosis.

Pharmacokinetic Properties

5.2   Pharmacokinetic properties
Absorption
Since the ingredients of Compound Sodium Lactate are infused intravenously their bioavailability is 100 %.

Distribution
Administration of Compound Sodium Lactate directly results in replenishment of the interstitial space which amounts to about 2/3 of the extracellular space. Only 1/3 of the administered volume stays in the intravascular space. Thus the solution has a short haemodynamic effect.
Biotransformation, elimination
Potassium, sodium, and chloride are mainly excreted in urine but small amounts are lost via the skin and also the intestinal tract. Especially surgery results in increased urinary excretion of potassium while water and sodium is retained.

Calcium is mainly excreted via the functioning kidneys. Small amounts are lost via the skin, hair, and nails. Calcium passes the placenta and is excreted into breast-milk.

Lactate is converted to bicarbonate and CO2, both are normal body constituents.
Plasma concentrations of bicarbonate and lactate are regulated by the kidneys and the plasma concentration of CO2 is regulated by the lung. Lactate metabolism is impaired in states of hypoxia and in liver insufficiency.