indication

Defibrotide is used to treat or prevent a failure of normal blood flow (occlusive venous disease, OVD) in the liver of patients who have had bone marrow transplants or received certain drugs such as oral estrogens, mercaptopurine, and many others.

pharmacology

Defibrotide is a deoxyribonucleic acid derivative extracted from mammalian organs, which has been developed for the treatment of a number of vascular disorders. It appears to increase fibrinolysis and may possess antithrombotic, antiatherosclerotic and anti-ischaemic actions, probably due to its ability to selectively increase prostaglandin I2 and E2 levels and to increase tissue plasminogen activator and decrease plasminogen activator inhibitor function. Defibrotide is available as an intravenous and intramuscular preparation, and also as an oral formulation for long term use.

mechanism of action

The drug appears to prevent the formation of blood clots and to help dissolve blood clots by increasing levels of prostaglandin I2, E2, and prostacyclin, altering platelet activity, increasing tissue plasminogen activator function, and decreasing activity of tissue plasminogen activator inhibitor. Prostaglandin I2 relaxes the smooth muscle of blood vessels and prevents platelets from adhering to each other. Prostaglandin E2 at certain concentrations also inhibits platelet aggregation. Moreover, the drug provides additional beneficial anti-inflammatory and antiischemic activities as recent sudies have shown. It is yet unclear, if the latter effects can be utilized clinically (e.g., treatment of ischemic stroke).

absorption

Bioavailability is 58-70% following oral administration, compared to parenteral forms (i.v. and i.m. = 100%).

half life

t1/2-alpha = minutes (10-20 minutes in rat); t1/2-beta = a few hours