Vorapaxar
Zontivity
Protease-activated receptor-1 (PAR-1) antagonist — antiplatelet
Blocks the thrombin platelet receptor (PAR-1) → inhibits thrombin-mediated aggregation without affecting the coagulation cascade itself.
Indications
- •Secondary CV prevention (prior MI or PAD) on top of ASA/clopidogrel
Dosing
| Context | Adult | Pediatric |
|---|---|---|
| Maintenance | 2.08 mg PO daily | — |
Pharmacokinetics
Very long effective half-life (~8 days) — antiplatelet effect persists for weeks after stopping.
Side effects
- !Bleeding (including ICH)
- !Effect lingers weeks (no practical reversal)
Contraindications
- ×History of stroke/TIA or ICH (contraindicated — bleeding)
- ×Active bleeding
Clinical pearls
- ★Extremely long-acting — the antiplatelet effect persists for WEEKS; there is no useful reversal.
- ★Contraindicated with any history of stroke/TIA/ICH.
Other drugs in Antiplatelets
- Aspirin
Irreversibly acetylates COX-1 → blocks thromboxane A2 for the platelet's lifespan (~7–10 days). Antiplatelet effect at low dose; analgesic/anti-inflammatory at high dose.
- Clopidogrel
Prodrug → active metabolite (CYP2C19) irreversibly blocks the platelet P2Y12 ADP receptor for the platelet lifespan.
- Prasugrel
Prodrug → active metabolite irreversibly blocks P2Y12. More potent + more consistent than clopidogrel (not CYP2C19-limited), but more bleeding.
- Ticagrelor
Directly and REVERSIBLY inhibits P2Y12 (not a prodrug, not thienopyridine). Faster onset/offset than clopidogrel.
- Ticlopidine
Irreversibly blocks P2Y12. Largely replaced by clopidogrel due to hematologic toxicity.
- Abciximab
Fab fragment that irreversibly blocks the platelet GP IIb/IIIa receptor → prevents fibrinogen cross-linking (final common pathway of aggregation).
- Eptifibatide
Reversibly blocks GP IIb/IIIa (final common pathway of platelet aggregation). Short-acting.
- Dipyridamole
Inhibits platelet PDE (↑ cAMP) and adenosine reuptake (↑ adenosine → vasodilation). Weak antiplatelet; also a coronary vasodilator used in stress testing.
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