Anti-platelet

Question 1

What is an example of an anti-platelet

Answer 1

Aspirin, clopidogrel

Question 2

What are the indications for use

Answer 2

• Acute coronary syndrome/ acute ischaemic stroke (rapid platelet aggregation can prevent or limit arterial thrombosis + reduce subsequent mortality)
• CV, cerebrovascular, peripheral arterial pts –> secondary prevent thrombotic event
• AF - prevent intracardiac thrombus/ embolic stroke where NOACs or OAC contraindicated
• Control mild-to-moderate pain + fever

Question 3

When do thrombotic events occur

Answer 3

When platelet rich thrombus forms in atheromatous arteries and occludes the circulation

Question 4

what is the mechanism of action

Answer 4

• Aspirin irreversibly inhibits cyclooxygenase (COX) –> reduce prod pro-aggregatory factor thromboxane (from arachidonic acid) –> reduce platelet aggregation
• Occurs at low doses + last lifetime of platelet

Question 5

What are the side effects

Answer 5

• GI irritation (most common)
• GI ulceration + haemorrhage
• Hypersensitivity –> bronchospasm
• Regular high dose –> tinnitus
• Life threatening in overdose

Question 6

What are the contra-indications

Answer 6

• Children under 16yrs (risk of Reye’s syndrome - affects liver and brain)
• Aspirin hypersensitivity (e.g. bronchospasm to aspirin or NSAIDs)
• 3rd trimester of pregnancy (prostaglandin inhibition ~~> premature closure ductus arteriosus)

CAUTION

• Peptic ulceration
• Gout

Question 7

What are some interactions

Answer 7

Caution when in combination with other antiplatelets (clopidogrel) or anticoagulants (heparin, warfarin)