Gb IIb/IIIa Inhibitors (STEMI/NSTEMI/UA) Flashcards
GP IIb/IIIa Inhibitors
Indications
Conformational changes in receptor allow binding with
- Fibrin
- Thrombin
- VWF
Binding triggers:
- Adhesion
- Activation
- Aggregation of platelets
Efficacy order!
- anti platelet
- UA/NSTEMI
Receptor blocking determines antiplatelet efficacy (abciximab>eptifibatide>tirofiban),
Clinical efficacy (UA/NSTEMI): (eptifibatide = tirofiban > abciximab),
and bleeding
GP IIb/IIIa Inhibitors
CI
CI: active or recent bleed 4-6weeks Hemorrhagicaccident CVA in 30 days- 2 ys Severe HTN >180/110 Major surgery/trauma in past 4-6 weeks Thrombocytopenia Bleeding diathesis/warfarin with elevated INR Renal insufficiency/failure
Eptifibatide MOA
Cyclic, small molecule
GP IIb/IIIa receptor antagonist
Selective
Reversible
Competitive inhibition
Temporarily blocks fibrin cross linking btwn active Gp Receptors
Eptifibatide Indications
Medical therapy in NSTEMI ACS with herparin, ASA +/- PCI and stenting
Eptifibatide Metabolism
Half life 1.1-2.5 hrs
(2 half lives at 5 hrs is 75% gone.. 90% gone is 3.3 half lives)
RENAL elimination
Platelet function returns within 4-12 hrs of D/C
Eptifibatide DI/CI/ Caution
Caution: aPTT>/= 45 seconds
CrCl less than 50
Eptifibatide SE
Bleeding (10%)
Eptifibatide considerations
Reduce MI/death by 20% after PCI for ACS when used with ASA
Tirofiban MOA
Nonpeptide, small molecule GP IIb/IIIa receptor antagonist Selective Reversible Competitive inhibition
Temporarily blocks fibrin cross linking btwn active Gp Receptors
Tirofiban Indications
Medical therapy in NSTEMI ACS with herparin, ASA +/- PCI and stenting
Tirofiban Metabolism
Infusion runs for up to 24 hours after PCI
Half life is 2 hrs
RENAL elimination
Platelet function returns within 4-12 hours of D/C
Tirofiban DI/CI/ Caution
Caution:
Platelets /= 45 secs
CrCl less than 30
Tiro Thirty- TT
Tirofiban considerations
Reduce MI/death by 20% after PCI for ACS when used with ASA
Abciximab MOA
Mouse monoclonal antibody gragment
Binds platelet GP IIb/IIIa receptor to inhibit activation and aggregation via fibrin crosslinking—steric hinderance prevents interactions btwn GP and vironectin recptors and other molecules (VW factor)
Binds platelet GP ab3 mediated thrombin generation
Clot retraction and smooth muscle cell proliferation
Amiximab Indications
Use with heparin and ASA in NSTMEI and STEMI ACS
Only in cath lab!
(to go home use asa, clipidogrel, adp inhibitors, prasugril, tacagrilor)
Amiximab Metabolism
Platelet inhibition exceeds 90% during infusion
binds and dissociates rapidly
steric hindrance of GP receptor
half life 10-30 min
platelet function returns in 48 hrs
Amiximab CI/DI/Precaution
CI: active bleeding
GI/GU bleed, trauma, surgery within 6 weeks
Anticoag in last 7 days
Precaution:
-Hypersensitivity reactions, TCP, rebound thrombosis observed with abciximab antibodies
-Heparin doses adjusted to minimize bleeding
increased risk of bleeding events when used with clopidogrel, lytics, longer PCI procedure
Amiximab Considerations
*50% reduction in total CV events but mortality is offset by adverse bleeding events
antibody remains bound to receptor aIIbB3
major hemorrhage varies and with heparin intensity, surgical pts at risk
reverse with platelets when needed
TCP in 2% of pts
