Pharmacological properties : תכונות פרמקולוגיות

Pharmacodynamic Properties

5.1     Pharmacodynamic properties

Pharmaco-therapeutic group:
Solutions for parenteral nutrition, carbohydrates, ATC code: B05B A03 
Glucose is metabolised ubiquitously as the natural substrate of the cells of the body. Under physiological conditions glucose is the most important energy-supplying carbohydrate with a caloric value of approx. 17 kJ/g or 4 kcal/g. Nervous tissue, erythrocytes and the medulla of the kidneys are amongst the tissues with an obligate requirement for glucose. In adults, the normal concentration of glucose in blood is 60 – 100 mg/100 ml, or 3.3 – 5.6 mmol/l (fasting).

Glucose serves to maintain the blood glucose level and for the synthesis of important body components. It serves for the synthesis of glycogen, the storage form of glucose. Primarily insulin, glucagon, glucocorticosteroids and catecholamines are involved in the regulation of the blood glucose concentration.

A normal electrolyte and acid-base status is a prerequisite for the optimal utilisation of administered glucose. So acidosis, in particular, can indicate impairment of oxidative glucose metabolism.

Metabolism of glucose and electrolytes are closely related to each other. Potassium, magnesium and phosphate requirements may increase and may therefore have to be monitored and supplemented according to individual needs. Especially cardiac and neurological functions may be impaired without supplementation.

Glucose intolerance may occur under pathological conditions, e.g. diabetes mellitus and metabolic stress (e.g. intra-, and postoperatively, severe disease, injury, sepsis). Severity of hyperglycaemia and glucosuria are related to the severity of the pathological state.

Infusion of higher concentrated glucose solutions can aggravate brain damage and cerebral oedema in cases of head injury, cerebrovascular accidents and ischemia.

Pharmacokinetic Properties

5.2     Pharmacokinetic properties

On infusion glucose is first distributed in the intravascular space and then is taken up into the intracellular space.

In glycolysis, glucose is metabolised to pyruvate or to lactate. Lactate can be partially re-introduced into the glucose metabolism (Cori cycle). Under aerobic conditions pyruvate is completely oxidised to carbon dioxide and water. The final products of the complete oxidation of glucose are eliminated via the lungs (carbon dioxide) and the kidneys (water).

Practically no glucose is excreted renally by healthy persons. In pathological metabolic conditions (e.g. diabetes mellitus, postaggression metabolism) associated with hyperglycaemia, glucose is also excreted via the kidneys (glucosuria) when the maximum tubular resorption capacity (at blood glucose levels higher than 180 mg/100 ml or 10 mmol/l) is exceeded.