GP IIb/ IIIa inhibitors are the select group of antiplatelet agents which are used in injectable forms only. They block the final step of platelet activation and cross-linking by Fibrinogen and vonWilbrand Factor.

1. GP IIb / IIIa inhibitors-An overview
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2. Acknowledgements
Sincere thanks to
• Dr Elangovan G
• Prof Nachiyappan
• Dr Sumathi E
• Dr Anandaraja S
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3. Glycoprotein IIb/IIIa receptors
• Alternate name: Integrin OR αIIbβ3
• Function: Responsible for final platelet
activation - Binds Fibrinogen and Vwf to form
platelet cross-links and platelet plug
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4. GP IIb / IIIa inhibitors
• Inhibitors:
1) Abciximab- Irreversible inhibitor
2) Eptifibatide- Reversible inhibitor
3) Tirofiban- Reversible inhibitor
They block the final step of platelet activation
and cross-linking by Fibrinogen and vonWilbrand
Factor.
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5. In Low risk pts
• 2 pronged attack with DAPT, given
UPSTREAM will suffice
• Whereas in high risk PCI, 3 pronged attack
essential
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6. 3 PRONGED ATTACK - NECESSARY
• CYCLOOXYGENASE INHIBITOR – ASPIRN
• ADP RECEPTOR ANTAGONIST – CLOPIDOGREL,
PRASUGREL, TICAGRELOR, CANGRELOR
• GP IIb/IIIa inhibitor – Most effective, because
they inhibit platelet at final common receptor
• Because I V only use- Used in intraprocedural
and post procedure periods
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7. Abciximab
• Developed as an antibody to c7E3 mouse
• Humanized - Murine monoclonal antibody
• Abciximab binds to vitronectin found on platelets
and vessel wall endothelial and smooth muscle
cells
• Short plasma half life, t1/2- 10 to 30 mnts
• Stored between 2-8 centigrade
• Irreversible inhibition
• Platelet aggregation returns after 96 to 120 hrs
• Functional half life – upto 7 days
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8. Abciximab - contd
• Dose: 1) PCI - 0.25mg/kg iv bolus 10- 60 mnts
before, followed by 0.125micgm/kg/mnt,
maximum of 10micgm/mnt for 12 hrs
• 2) USAP not relenting to medical measures and
pts planned for PCI- 0.25mg/kg iv bolus followed
by 10micgm/mnt for 18- 24 hr, concluding 1 hr
after PCI
• Peak action at 2hrs after bolus dose
• Action can be reversed by platelet transfusion
• note : it comes around 12.5 mg for 50 kg person
as bolus followed by 0.5 mg / hr
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9. Dosing of Heparin
• Reduced dose with all GP inhibitors
• Initial heparin dose 70 units/kg body wt,
maximal dose of 7000 units, subsequent dose
20 u/kg,
• keep ACT around 200secs.
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10. Contraindications
• Active bleeding
• Recent surgery, trauma, GI or GU Bleeding ( <6 weeks)
• CVA within 2 years or CVA with significant neurological
deficit
• Bleeding diathesis
• Use of oral anticoagulants < 7 days, unless PT <1.2× Control
• Thrombocytopenia <100,000
• Documented history of vasculitis
• Hypersensitivity to Murine proteins
• Uncontrolled hypertension
• Intracranial neoplasm, aneurysm or A V Malformations
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11. Eptifibatide
• Developed from venom of rattle snake
• Reversible inhibition of platelets
• Short half- life & Stored between 2- 8 centigrade
• Loading dose – 180 micgm/kg over 1-2 mnts,
followed by 2 micgm/kg/mnt until discharge or
upto 72 hrs or initiation of CABG
• Pts weighing >120kg receive a max bolus of 22.6
mg followed by infusion of 15 mg/ hr
• Renal impairment CrCl < 50 ml- bolus 180mcg/kg &
infusion 1 mcg/kg/mnt
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12. Tirofiban
• Nonpeptide, less likely to cause allergy, t1/2-2 hrs
• Rapid onset and short duration of action
• Coagulation factors return after 4- 8 hrs
• Can be stored at room temperature unlike other
two GP IIb/IIIa inhibitors
• Bolus 25 mcg/ kg over 3 mnts followed by 0.15
mcg/kg/mnt for upto 18 hrs
• Renal impairment, cr cl <60 ,ml/min, 25 mcg/kg
loading, 0.075 mcg/kg/mnt for 18 hrs
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13. Heparin dosage For Eptifibatide and
Tirofiban
• Initial dose 5000 units bolus
• Followed - 1000 u/hr, keep APTT twice the control
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14. Recommendations
• Upstream GP IIb/IIIa Inhibitors may be used in
high risk patients undergoing PCI
• In STEMI, its use should be considered for bail
out on evidence of Post PCI thrombotic
complications
• Its use in NO REFLOW / SLOW FLOW is
controversial
• In NSTE-ACS, pre treatment is not indicated
• In NSTE- ACS, can be considered for bail out
situations
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15. Take home message .........
• Abciximab can cause – serious
Thrombocytopenia
• GP inhibitors use in non high risk PCI –is
modest /NA
• Their use should be continued with UFH or
LMWH and not with Bivalirudin
• If Bivalirudin is chosen, it only increases
bleeding risks but no added survival benefit
• Monitoring of aPTT or ACT to be done
throughout the heparin therapy
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