Desirudin clinical pharmacology

Desirudin
IPRIVASK® FDA Package Insert
Indications and Usage
Dosage and Administration
Contraindications
Warnings and Precautions
Adverse Reactions
Drug Interactions
Use in Specific Populations
Overdosage
Description
Clinical Pharmacology
Nonclinical Toxicology
Clinical Studies
How Supplied/Storage and Handling
Labels and Packages
Clinical Trials
ClinicalTrials.gov

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Sheng Shi, M.D. [2]

Clinical Pharmacology

Mechanism of Action

Desirudin is a selective inhibitor of free circulating and clot-bound thrombin. The anticoagulant properties of desirudin are demonstrated by its ability to prolong the clotting time of human plasma. One molecule of desirudin binds to one molecule of thrombin and thereby blocks the thrombogenic activity of thrombin. As a result, all thrombin-dependent coagulation assays are affected. Activated partial thromboplastin time (aPTT) is a measure of the anticoagulant activity of desirudin and increases in a dose-dependent fashion. The pharmacodynamic effect of desirudin on proteolytic activity of thrombin was assessed as an increase in aPTT. A mean peak aPTT prolongation of about 1.38 times baseline value (range 0.58 to 3.41) was observed following subcutaneous b.i.d. injections of 15 mg desirudin. Thrombin time (TT) frequently exceeds 200 seconds even at low plasma concentrations of desirudin, which renders this test unsuitable for routine monitoring of Iprivask therapy. At therapeutic serum concentrations, desirudin has no effect on other enzymes of the hemostatic system such as factors IXa, Xa, kallikrein, plasmin, tissue plasminogen activator, or activated protein C. In addition, it does not display any effect on other serine proteases, such as the digestive enzymes trypsin, chymotrypsin, or on complement activation by the classical or alternative pathways.

Pharmacokinetic Properties

Pharmacokinetic parameters were calculated based on plasma concentration data obtained by a non-specific ELISA method that does not discriminate between native desirudin and its metabolites. It is not known if the metabolites are pharmacologically active.

Absorption

The absorption of desirudin is complete when subcutaneously administered at doses of 0.3 mg/kg or 0.5 mg/kg. Following subcutaneous administration of single doses of 0.1 to 0.75 mg/kg, plasma concentrations of desirudin increased to a maximum level (Cmax) between 1 and 3 hours. Both Cmax and area-under-the-curve (AUC) values are dose proportional.