Pharmacological properties : תכונות פרמקולוגיות

Pharmacodynamic Properties

5.1. Pharmacodynamic properties

Dexamethasone Kalceks belongs to the therapeutic group H02AB02.

Dexamethasone is a fluorinated corticosteroid with a long duration of action, high anti- inflammatory and immunosuppressive potency and low mineralocorticoid activity. Glucocorticoids cause profound and varied metabolic effects. They also modify the immune response to various stimuli.


This drug inhibits the synthesis of prostaglandins and leukotrienes, substances that mediate vascular and cellular processes of inflammation and immune response. Therefore, they reduce vasodilation and the typical liquid exudate of inflammatory processes, leukocyte activity, aggregation and degranulation of neutrophils, release of hydrolytic enzymes by lysosomes, etc.
Both actions are due to the inhibition of the synthesis of phospholipase A2, an enzyme responsible for releasing polyunsaturated fatty acids, precursors of prostaglandins and leukotrienes.


Dexamethasone, like the rest of glucocorticoids, binds to cytoplasmic glucocorticoid receptors activating them. As a consequence, different neutral endopeptidases, plasminogen activator inhibitors, lipocortin, etc., are mobilized.


Glucocorticoids decrease the stability of certain RNA-messenger molecules, altering gene transcription. Genes affected by this action include the synthesis of collagenase, elastase, plasminogen activator, type II cyclooxygenase, cytokines and chemokines.

Other actions

Pharmacological doses of exogenous corticosteroids produce hypothalamic-pituitary-adrenal (HPA) axis suppression through a negative feedback mechanism.

Glucocorticoids stimulate protein catabolism and induce the enzymes responsible for amino acid metabolism.

Glucocorticoids increase glucose availability through various actions that lead to increased hepatic glycogen stores, blood glucose concentrations, and insulin resistance.

Glucocorticoids increase lipolysis and mobilize fatty acids from adipose tissue, causing an increase in plasma fatty acid concentrations. They also decrease bone formation and increase bone resorption.

Dexamethasone, the active ingredient in Dexamethasone Kalceks, is 30 times more potent than cortisone, 25 times more potent than hydrocortisone, 6 times more potent than prednisone and prednisolone, and 5 times more potent than methylprednisolone and triamcinolone.

Pharmacokinetic Properties

5.2. Pharmacokinetic properties
Dexamethasone is a corticosteroid with a long duration of action, since its effects are maintained for up to 72 hours, its total clearance varies between 2.8 and 3.5 mg/minute/kg, the elimination half-life is 3-4 hours (limits of 3 to 6 hours for adults, 2.8-7.5 hours for 8-16 years and 2.3-9.5 hours for children under 2 years) and the biological half-life of 36-54 hours.

After intramuscular administration, peak serum levels are reached within one hour, it is widely distributed throughout the body with a degree of binding to plasma proteins of 70%, it diffuses through the placental and blood-milk barriers, the volume of distribution is 2 l/kg, it is metabolized in the liver (hydroxylation) and eliminated in the urine, 8% unchanged, and to a lesser extent in the bile.