ICU Primary PrepCast #013- Haematology Part 2
Nov 21, 2018
Maddi and Swapnil dive deep into hematology, covering the intriguing role of platelets in hemostasis. They break down the mechanics of antiplatelet agents like aspirin and clopidogrel, touching on activation and potential side effects. The duo also explores thrombolytics, differentiating between various tPAs and their clinical uses. Additionally, they discuss antifibrinolytics like tranexamic acid, highlighting their applications in critical scenarios. Tune in for a mix of science, humor, and valuable insights!
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Platelet Plug Mechanism
- Platelets form a plug via adhesion, activation, and aggregation after endothelial injury using glycoprotein receptors and ADP/TXA2 feedback.
- Prostacyclin and nitric oxide from intact endothelium prevent platelet adhesion to healthy vessels.
Antiplatelet Classes And Durations
- Antiplatelet drugs act at distinct targets: COX inhibitors, PDE inhibitors, ADP receptor blockers, and GPIIb/IIIa antagonists.
- Duration varies: aspirin 7–10 days, dipyridamole ~24 hours, clopidogrel/prasugrel 7–10 days, ticagrelor ~5 days.
Aspirin Pharmacology Essentials
- Aspirin irreversibly acetylates platelet COX‑1, reducing thromboxane A2 and producing antiplatelet effect lasting platelet lifespan (7–10 days).
- It is rapidly absorbed, hydrolysed to salicylate, and shows dose-dependent renal elimination with pH‑dependent excretion.