CLOPIDOGREL

Question 1

Clopidogrel - what type of drug is it?

Answer 1

Antiplatelet (ADP-Receptor Antagonist)

Question 2

Clopidogrel - indications (first-line treatment)

Answer 2

Acute coronary syndrome (ACS)
MONA - Aspirin + Clopidogrel
Why? rapid inhibition of platelet aggregation > prevent/limit arterial thrombosis > reducing mortality

Question 3

Clopidogrel - indications (SECONDARY prevention)

SAME AS ASPIRIN

Answer 3

For long term secondary prevention of thrombotic arterial events in patients with:
→ Cardiovascular disease
→ Cerebrovascular disease
→ Peripheral arterial disease

Can be alone OR in combination with aspirin (dual-antiplatelet therapy)

Question 4

Clopidogrel - MOA

Answer 4

ADP-receptor antagonist

1) Clopidogrel irreversibly binds to ADP receptors on the surface of platelets
2) This prevents platelet aggregation
3) This reduces the risk of arterial occlusion

Question 5

Clopidogrel - Adverse effect (most common and common)

Answer 5

→ Bleeding (most common)

→ GI upset: dyspepsia, abdominal pain, diarrhoea (common)

Question 6

Clopidogrel - Adverse effect (rare)

Answer 6

→ Thrombocytopenia (low blood platelet count) (rare)

Question 7

Clopidogrel - Interactions

Answer 7

CAUTION with:
→ CYP inhibitors 
Why? Clopidogrel is a prodrug that requires cytochrome P450 (CYP) enzymes to activate and enable its antiplatelet effect - use of CYP inhibitor would essentially inhibit Clopidogrel prodrug activation
Examples:
- Omeprazole 
- Ciprofloxacin 
- Erythromycin 
- Some antifungals 
- Some SSRIs

→ Other antiplatelet drugs, anticoagulant drugs (e.g.- heparin) and NSAIDs
Why? Increased risk of bleeding

Question 8

Clopidogrel - why is caution required when giving a patient clopidogrel who is already on CYP inhibitors

Answer 8

Clopidogrel is a prodrug that requires cytochrome P450 (CYP) enzymes to activate and enable its antiplatelet effect - use of CYP inhibitor would essentially inhibit Clopidogrel prodrug activation

Question 9

Clopidogrel - why is caution required with the use of clopidogrel with other antiplatelet drugs

Answer 9

Increased risk of bleeding

Question 10

Clopidogrel - caution

Answer 10

→ Increased bleeding risk

→ Prior to elective surgery or other invasive procedures

→ Patients with renal or hepatic impairments

Question 11

Clopidogrel - contraindications

Answer 11

AVOID in people with active bleeding

Question 12

What gastroprotection can you give a patient that is taking both clopidogrel and aspirin? and why?

Answer 12

Lansoprazole OR Pantoprazole

DO NOT GIVE OMEPRAZOLE
Why? Lansoprazole or pantoprazole are less likely to inhibit Clopidogrel activation

Question 13

Which other antiplatelet drug is clopidogrel usually given alongside and why can we give them both together?

Answer 13

Aspirin

Clopidogrel does NOT act on the COX pathway and therefore works synergistically with aspirin

Question 14

what is the purpose of Clopidogrel in the context of coronary arterial stents

Answer 14

To prevent occlusion of coronary artery stents - usually in combination with aspirin (dual-antiplatelet therapy)