Core pharmacology

Class Group

Antiplatelet

Legacy Cicm Level

Level 3

Introduction

ADP Receptor Antagonist - Thienopyridine

Main Action

Platelet inhibition

Mechanism of action

Prodrug. Hepatic activation to active agent (Thiol derivative, by oxidation and hydrolysis) which is an ADP receptor antagonist
- Irreversible inhibition of P2Y12 receptor at platelet surface → Inhibits activation of GPIIb/IIIa → Inhibits platelet activation

Adverse Effects Toxicity

Bleeding
TTP
Agranulocytosis, Neutropenia
Significant drug interactions as requires activation by CYP450

Absorption

- PO. BA 50%
- 600mg loading. 75mg maint.

Protein binding

95% protein binding,

Volume of distribution

Vd unknown

Metabolism

- Hepatic CYP450 2C19 + Esterases to Inactive metab

Excretion

- Renal and faecal elimination

Half-life

- T1/2b 7 hours parent drug (30mins metab) Dur: life of platelet