Clopidogrel

Question 1

What are common indications for the use of clopidogrel?

Answer 1

• Treatment of ACS
• Prevent occlusion of stents
• Long term prevention of thrombotic arterial disease
• Reduce risk of intracardiac thrombus/embolic stroke in AF

Question 2

How does Clopidogrel work?

Answer 2

Prevents platelet aggregation and reduces risk of arterial occlusion by binding irreversibly to ADP receptors on platelets

Question 3

What are important adverse effects of clopidogrel?

Answer 3

• Bleeding
• GI upset - dyspepsia, abdo pain, diarrhoea
• Thrombocytopenia

Question 4

When is clopidogrel contraindicated?

Answer 4

Active bleeding

Question 5

What drugs can interact with clopidogrel?

Answer 5

• Cytochrome P450 inhibitors
  
  • Omeprazole
  • Ciprofloxacin
  • Erythromycin
  • SSRI’s
• Antiplatelet drugs
• Anticoagulants
• NSAIDs

Question 6

How is clopidogrel administered?

Answer 6

Oral only

Question 7

If you required rapid anti-platelet action using clopidogrel, how would you initiate treatment?

Answer 7

300mg loading dose in once only section, followed by 75 mg daily in regular section

Question 8

How long should dual antiplatelet therapy be continued for with a drug-eluting coronary stent in situ?

Answer 8

12 months - reduces risk of stent thrombosis

Question 9

If using clopidogrel for secondary prevention of MI, CVA or atherosclerotic events, what dose and how regularly would you give it?

Answer 9

75 mg daily

Question 10

How long before elective surgery should clopidogrel be stopped?

Answer 10

7 days - due to lifespan of platelet and irreversibilty of action of clopidogrel on platelets

Question 11

When would you give an initial loading dose of clopidogrel?

Answer 11

ACS

Question 12

What would you prescribe in tandem with antiplatelet therapy?

Answer 12

Gastroprotection

Question 13

What might you prescribe someone with a low risk of GI bleeding when given antiplatelet medication?

Answer 13

Ranitidine 150 mg Twice daily, if ineffective give lanzoprazole

Question 14

What might you prescribe as gastroprotection for those with high risk of GI bleeding on anti-platelet therapy?

Answer 14

Lansoprazole

Question 15

What are risk factors for GI bleeding on antiplatelet therapy?

Answer 15

• Gastrodudenal ulcer
• Previous GI bleeding
• Gastroduodenal perforation
• Concominant use of medications known to increase risk of GI bleeds
• Frailty +/- serious co-morbidities

Question 16

How long does it take for the antiplatelet effect of clopidogrel to wear off?

Answer 16

Lifespan of a platelet - 7-10 days - acts irreversibly