ANTIPLATELETS

Question 1

How do antiplatelet drugs work?

Answer 1

• Antiplatelet drugs decrease platelet aggregation
• inhibit thrombus formation in the arterial circulation
• faster-flowing vessels, thrombi are composed mainly of platelets with little fibrin

Question 2

Examples

Answer 2

• Aspirin
• Clopidogrel
• Prasugrel
• Ticagrelor
• Dipyridamole

Question 3

If the patient is at high risk of Gl bleeding and needs to take aspirin…

Answer 3

+ PPI

Question 4

What are the doses of Aspirin in acute
cardiovascular events and secondary prevention?

Answer 4

• 75mg daily for secondary prevention
• 300mg for stroke or MI

Question 5

What are the
contraindications for Aspirin?

Answer 5

• Active peptic ulceration
• Children under 16 years old (linked to Reye’s syndrome)
• Previous peptic ulceration
• History of hypersensitivity to Aspirin or other NSAIDs
• E.g. Attacks of asthma due to aspirin or NSAIDS

Question 6

When is there an exception to the use of Aspirin for under 16-year-olds?

Answer 6

Kawasaki disease

Question 7

What are the side effects of Aspirin?

Answer 7

• Bronchospasms (e.g.
  Asthma or COPD)
• Gastrointestinal haemorrhage
  (GI Bleeding)

Question 8

Aspirin: Interactions

Answer 8

Increased risk of bleeding
examples:
- Aspirin & Warfarin
- Aspirin & SSRIs (e.g.
Sertraline & Citalopram)
- Aspirin & NSAIDs

Question 9

Aspirin in pregnancy

Answer 9

Yes
- antiplatelet dose (75mg) caution in 3rd trimester
- avoid analgesic dose (300mg) in the last few weeks
- Aspirin OD or BD is indicated after 12 weeks of pregnancy to prevent pre-eclampsia

Question 10

What is an unlicensed loading dose of clopidogrel and in which instance it may be used?

Answer 10

• 600mg loading dose (instead of 300mg)
• It may be used in the prevention of atherothrombotic events in PCI in adjuct with aspirin
• The higher loading dose may be done to produce a more rapid effect

Question 11

When can clopidogrel be used as
monotherapy?

Answer 11

• ischaemic stroke (or who have peripheral arterial disease or multivascular disease
• MI ONLY if aspirin is contraindicated/not tolerated

Question 12

What are the common side effects of Clopidogrel?

Answer 12

Diarrhoea
Gl discomfort
haemorrhage (bleeding)
Skin reactions

Question 13

What are some interactions with clopidogrel?

Answer 13

• Warfarin
• SSRIS
• Omeprazole (moderate interaction)

Question 14

Can Dipyridamole be used in Myocardial infarction (MI)?

Answer 14

NO!
Only in stroke (ischaemic/TIA)

Question 15

Which formulation of Dipyrimadole is used in stroke/TIA?

Answer 15

Modified release capsules

Question 16

When are immediate release tablets of Dipyridamole used?

Answer 16

In combination with oral anticoagulation for prophylaxis of thromboembolism associated with prosthetic
heart valves

Question 17

What is a common side effect of
Dipyridamole?

Answer 17

• throbbing headache
• it is likely to disappear after continued use

Question 18

Can prasugrel and Ticagrelor be used in stroke?

Answer 18

No!
Only in Acute coronary syndromes (Unstable angina,
NSTEMI, STEMI)

Question 19

When are Prasugrel and Ticagrelor used?

Answer 19

• In combination with aspirin for prevention of atherothrombotic events in patients with ACS
• Alternative to clopidogrel in patients undergoing PCI (percutaneous coronary intervention)