Desirudin clinical pharmacology: Difference between revisions
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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. | 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. | ||
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===Distribution=== | |||
The pharmacokinetic properties of desirudin following intravenous (IV) administration are well described by a two- or three- compartment disposition model. Desirudin is distributed in the extracellular space with a volume of distribution at steady state of 0.25 L/kg, independent of the dose. Desirudin binds specifically and directly to thrombin, forming an extremely tight, non-covalent complex with an inhibition constant of approximately 2.6 x 10-13 M. Thus, free or protein bound desirudin immediately binds circulating thrombin. The pharmacological effect of desirudin is not modified when co-administered with highly protein bound drugs (>99%). | |||
===Metabolism=== | |||
Human and animal data suggest that desirudin is primarily eliminated and metabolized by the kidney. The total urinary excretion of unchanged desirudin amounts to 40 to 50% of the administered dose. Metabolites lacking one or two C-terminal amino acids constitute a minor proportion of the material recovered from urine (< 7%). There is no evidence for the presence of other metabolites. This indicates that desirudin is metabolized by stepwise degradation from the C-terminus probably catalyzed by carboxypeptidase(s) such as carboxypeptidase A, originating from the pancreas. Total clearance of desirudin is approximately 1.5 to 2.7 mL/min/kg following either subcutaneous or IV administration and is independent of dose. This clearance value is close to the glomerular filtration rate. | |||
===Elimination=== | |||
The elimination of desirudin from plasma is rapid after IV administration, with approximately 90% of the dose disappearing from the plasma within 2 hours of the injection. Plasma concentrations of desirudin then decline with a mean terminal elimination half-life of 2 to 3 hours. After subcutaneous administration, the mean terminal elimination half-life is also approximately 2 hours. | |||
<ref name="dailymed.nlm.nih.gov">{{Cite web | last = | first = | title = IPRIVASK (DESIRUDIN) KIT [MARATHON PHARMACEUTICALS, LLC] | url = http://dailymed.nlm.nih.gov/dailymed/lookup.cfm?setid=d768eca6-b25d-4aec-905f-b6a89e89ff29 | publisher = | date = | accessdate = 3 February 2014 }}</ref> | <ref name="dailymed.nlm.nih.gov">{{Cite web | last = | first = | title = IPRIVASK (DESIRUDIN) KIT [MARATHON PHARMACEUTICALS, LLC] | url = http://dailymed.nlm.nih.gov/dailymed/lookup.cfm?setid=d768eca6-b25d-4aec-905f-b6a89e89ff29 | publisher = | date = | accessdate = 3 February 2014 }}</ref> | ||
Revision as of 03:43, 3 February 2014
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.
 |
Distribution
The pharmacokinetic properties of desirudin following intravenous (IV) administration are well described by a two- or three- compartment disposition model. Desirudin is distributed in the extracellular space with a volume of distribution at steady state of 0.25 L/kg, independent of the dose. Desirudin binds specifically and directly to thrombin, forming an extremely tight, non-covalent complex with an inhibition constant of approximately 2.6 x 10-13 M. Thus, free or protein bound desirudin immediately binds circulating thrombin. The pharmacological effect of desirudin is not modified when co-administered with highly protein bound drugs (>99%).
Metabolism
Human and animal data suggest that desirudin is primarily eliminated and metabolized by the kidney. The total urinary excretion of unchanged desirudin amounts to 40 to 50% of the administered dose. Metabolites lacking one or two C-terminal amino acids constitute a minor proportion of the material recovered from urine (< 7%). There is no evidence for the presence of other metabolites. This indicates that desirudin is metabolized by stepwise degradation from the C-terminus probably catalyzed by carboxypeptidase(s) such as carboxypeptidase A, originating from the pancreas. Total clearance of desirudin is approximately 1.5 to 2.7 mL/min/kg following either subcutaneous or IV administration and is independent of dose. This clearance value is close to the glomerular filtration rate.
Elimination
The elimination of desirudin from plasma is rapid after IV administration, with approximately 90% of the dose disappearing from the plasma within 2 hours of the injection. Plasma concentrations of desirudin then decline with a mean terminal elimination half-life of 2 to 3 hours. After subcutaneous administration, the mean terminal elimination half-life is also approximately 2 hours. [1]
References
- ↑ "IPRIVASK (DESIRUDIN) KIT [MARATHON PHARMACEUTICALS, LLC]". Retrieved 3 February 2014.