Pharmacological properties : תכונות פרמקולוגיות

Pharmacodynamic Properties

5.1 Pharmacodynamic properties

Pharmacotherapeutic group: Antithrombotic agents: platelet aggregation inhibitors , excluding heparine.
ATC Code: B01 AC.

Iloprost is a prostacyclin analog. The following pharmacological effects have been observed: 
Inhibition of aggregation, platelet adhesion and degranulation, dilatation of arterioles and venules, increased capillary density and reduction of increased vascular permeability in the microcirculation; activation of fibrinolysis, inhibition of adhesion and migration of leukocytes after injury to endothelial tissue and diminished release of oxygen-containing free radicals.

The exact mechanism of action is unknown.

Pharmacokinetic Properties

5.2 Pharmacokinetic properties

• Distribution


Steady-state plasma levels of the drug are achieved in as little as 10-20 minutes after the start of an intravenous infusion. Steady- state plasma concentrations are linearly related to the infusion rate..
An infusion rate of 3 ng/kg/min obtains plasma concentrations of approximately 135 ± 24 pg/mL. . The plasma concentration of iloprost drops very rapidly after infusion is completed due to its high metabolism rate. Metabolic clearance of the substance from plasma is approximately 20 ± 5 ml/kg/min. The plasma terminal half-life is 0.5 hours, , so the concentration falls to less than 10% of the stead- state concentration two hours after the end of infusion.


Interactions with other medications at the level of plasma protein binding are unlikely because most of the iloprost binds to the albumin in blood plasma (protein binding: 60 %) and only extremely low concentrations of free iloprost are achieved. It is also highly unlikely for iloprost to modify the biotransformation of other drugs due to the low absolute dose and the metabolic pathways involved.

• Metabolism and elimination

Iloprost is metabolised mainly through beta oxidation of the carboxyl side chain. No unchanged fraction of the substance is eliminated.. The main metabolite is tetranor-iloprost, present in urine in free form and conjugated form as four diastereoisomers. Tetranor-iloprost is pharmacologically inactive. 80% of iloprost’s metabolites are excreted through the kidneys and 20% through the liver. Metabolites are eliminated from blood plasma and through the urine in two phases, for which half-lives of approximately two and five hours (plasma) and two and 18 hours (urine) have been calculated.

• Special populations

The pharmacokinetic characteristics of iloprost are not affected by a patient’s age or sex. However, in patients with cirrhosis of the liver and in those with chronic renal insufficiency requiring dialysis, iloprost clearance is 2-4 times less.