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Antiplatelets

1) Antiplatelet Drugs

  • COX Inhibitors
  • Prostaglandin Analogues (PGI2)
    • Treprostinil (Remoodulin)
  • Combos
    • Aspirin + Clopidogrel
    • 4 weeks after bare metal stent
    • 6 months after drug eluting stent
    • Unstable angina
    • Aspirin + Prasugrel
    • Patients undergoing PCI

A) COX Inhibitors

  • Acetylsalicylic Acid (Aspirin)
  • COX1 Inhibition (Thromboxane A2)
  • COX2 Inhibition at high doses
  • Overdose:
    • Gastric Lavage, Activated Charcoal
    • Alkalinization of the urine (IV Sodium Bicarb)
    • Goal of urine pH ≥7.5
    • Dialysis if Salicylate levels ≥90-100 with acute intoxication or ≥60 ng/mL in chronic administration
  • Reye Syndrome
    • Use of aspirin after a URI
    • Symptoms
    • Acute encephalopathy w/hepatic dysfunction occurring days after recovery
    • Heavy vomiting, delirium, fatty liver, seizures, coma
    • Liver failure with elevated AST, ALT
    • Increased PT, elevated ammonia, and hypoglycemia
    • ± Renal and heart failure, Increased ICP

B) PDE Inhibitors/Thromboxane Inhibitors

  • Cyclic AMP Interference
  • Dipyridamol (Persantine)
  • Blocks AMP BD, inhibit Platelet activation

C) PARI

  • Thrombin Receptor Interference, PAR-1 Antagonist
  • Vorapaxar (Zontivity)

D) P2Y12

  • ADP Receptor Antagonists (P2Y12 Inhibitors)
  • Binds platelet ADP receptor
    • Inhibits platelet aggregation
    • Used in aspirin intolerant or in coronary stents
  • Thienopyridine (IR)
    • Require CYP450 activation
  • Clopidogrel (Plavix)
  • Prasugrel (Effient)
    • 10x stronger, more rapid
    • More bleeding risk than clopidogrel
    • CI in ≥75 y/o, renal impaired, CVD
  • Ticlopidine (Ticlid)
  • Nucleotide/side analog (R)
    • Reversible, no activation needed to work
  • Ticagrelor (Brilinta)
    • More rapid onset, ≥ than clopidogrel
    • SE: Dyspnea MC
  • Cangrelor
    • Immediate onset – 1 hour

E) GIIb/IIIa Receptor Inhibitors

  • GP IIb/IIIa antagonists
  • Abciximab (ReoPro)
    • PCI w/o ADPRA, not renally cleared
    • Monoclonal antibody
  • Eptifibatide (Integrilin)
  • Tirofiban (Aggrastat)
    • High risk unstable angina- Eptifibutide (Integrilin)

F) PDE3 Inhibitors

  • Cilostazole (Pletal)
  • Only indicated in symptomatic claudication
  • CI: HF