Bivalirudin clinical pharmacology
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Jesus Rosario Hernandez, M.D. [2]
Clinical Pharmacology
12.1 Mechanism of Action
Angiomax directly inhibits thrombin by specifically binding both to the catalytic site and to the anion-binding exosite of circulating and clot-bound thrombin. Thrombin is a serine proteinase that plays a central role in the thrombotic process, acting to cleave fibrinogen into fibrin monomers and to activate Factor XIII to Factor XIIIa, allowing fibrin to develop a covalently cross-linked framework which stabilizes the thrombus; thrombin also activates Factors V and VIII, promoting further thrombin generation, and activates platelets, stimulating aggregation and granule release. The binding of Angiomax to thrombin is reversible as thrombin slowly cleaves the Angiomax-Arg3-Pro4 bond, resulting in recovery of thrombin active site functions.
In in vitro studies, Angiomax inhibited both soluble (free) and clot-bound thrombin, was not neutralized by products of the platelet release reaction, and prolonged the activated partial thromboplastin time (aPTT), thrombin time (TT), and prothrombin time (PT) of normal human plasma in a concentration-dependent manner. The clinical relevance of these findings is unknown.
12.2 Pharmacodynamics
In healthy volunteers and patients (with ≥70% vessel occlusion undergoing routine PTCA), Angiomax exhibited dose- and concentration-dependent anticoagulant activity as evidenced by prolongation of the ACT, aPTT, PT, and TT. Intravenous administration of Angiomax produces an immediate anticoagulant effect. Coagulation times return to baseline approximately 1 hour following cessation of Angiomax administration.
In 291 patients with ≥70% vessel occlusion undergoing routine PTCA , a positive correlation was observed between the dose of Angiomax and the proportion of patients achieving ACT values of 300 sec or 350 sec. At an Angiomax dose of 1 mg/kg IV bolus plus 2.5 mg/kg/h IV infusion for 4 hours, followed by 0.2 mg/kg/h, all patients reached maximal ACT values >300 sec.
12.3 Pharmacokinetics
Angiomax exhibits linear pharmacokinetics following IV administration to patients undergoing PTCA. In these patients, a mean steady state Angiomax concentration of 12.3 ± 1.7 mcg/mL is achieved following an IV bolus of 1 mg/kg and a 4-hour 2.5 mg/kg/h IV infusion. Angiomax does not bind to plasma proteins (other than thrombin) or to red blood cells. Angiomax is cleared from plasma by a combination of renal mechanisms and proteolytic cleavage, with a half-life in patients with normal renal function of 25 min.
The disposition of Angiomax was studied in PTCA patients with mild, moderate, and severe renal impairment. Drug elimination was related to glomerular filtration rate (GFR). Total body clearance was similar for patients with normal renal function and with mild renal impairment (60-89 mL/min). Clearance was reduced in patients with moderate and severe renal impairment and in dialysis-dependent patients (See Table 6 for pharmacokinetic parameters).
Angiomax is hemodialyzable, with approximately 25% cleared by hemodialysis.[1]
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References
- ↑ "ANGIOMAX (BIVALIRUDIN) INJECTION, POWDER, LYOPHILIZED, FOR SOLUTION [THE MEDICINES COMPANY]". Retrieved 10 March 2014.
Adapted from the FDA Package Insert.