Abciximab, eptifibatide, and tirofiban exhibit dose-dependent potencies to dissolve platelet aggregates

J Cardiovasc Pharmacol. 2003 Apr;41(4):586-92. doi: 10.1097/00005344-200304000-00011.


Platelet GPIIb/IIIa antagonists are not only used to prevent platelet aggregation, but also in combination with thrombolytic agents for the treatment of coronary thrombi. Recent data indicate a potential of abciximab alone to dissolve thrombi in vivo. We investigated the potential of abciximab, eptifibatide, and tirofiban to dissolve platelet aggregates in vitro. Adenosine diphosphate (ADP)-induced platelet aggregation could be reversed in a concentration-dependent manner by all three GPIIb/IIIa antagonists when added after the aggregation curve reached half-maximal aggregation. The concentrations chosen are comparable with in vivo plasma concentrations in clinical applications. Disaggregation reached a maximum degree of 72.4% using 0.5 microg/ml tirofiban, 91.5% using 3.75 microg/ml eptifibatide, and 48.4% using 50 microg/ml abciximab (P < 0.05, respectively). A potential fibrinolytic activity of the GPIIb/IIIa antagonists was ruled out by preincubation with aprotinin or by a plasma clot assay. A stable model Chinese hamster ovary (CHO) cell line expressing the activated form of GPIIb/IIIa was used to confirm the disaggregation capacity of GPIIb/IIIa antagonists found in platelets. Not only abciximab, but also eptifibatide and tirofiban have the potential to disaggregate newly formed platelet clusters in vitro. Because enzyme-dependent fibrinolysis does not appear to be involved, competitive removal of fibrinogen by the receptor antagonists is the most likely mechanism.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Abciximab
  • Animals
  • Antibodies, Monoclonal / pharmacology*
  • CHO Cells
  • Cricetinae
  • Dose-Response Relationship, Drug
  • Eptifibatide
  • Humans
  • Immunoglobulin Fab Fragments / pharmacology*
  • Peptides / pharmacology*
  • Platelet Aggregation / drug effects*
  • Platelet Aggregation / physiology
  • Platelet Glycoprotein GPIIb-IIIa Complex / antagonists & inhibitors
  • Platelet Glycoprotein GPIIb-IIIa Complex / physiology
  • Tirofiban
  • Tyrosine / analogs & derivatives
  • Tyrosine / pharmacology*


  • Antibodies, Monoclonal
  • Immunoglobulin Fab Fragments
  • Peptides
  • Platelet Glycoprotein GPIIb-IIIa Complex
  • Tyrosine
  • Tirofiban
  • Eptifibatide
  • Abciximab