CVS: aspirin, anti-platelet drugs

Question 1

Indications of aspirin?

Answer 1

ACS (300mg then 75mg) & Acute ischaemic stroke (300mg 2weeks)

Cardiovascular, cerebrovascular, and peripheral arterial disease

Question 2

MOA of aspirin?

Answer 2

Aspirin irreversibly inhibits cyclooxygenase (COX) to reduce production of the pro-aggregatory factor thromboxane from arachidonic acid.
-This reduces platelet aggregation and the risk of arterial blockage.

The antiplatelet effect occurs at low doses and lasts for the lifetime of a platelet and only wears off as new platelets are made.

Question 3

Adverse effects of aspirin?

Answer 3

• GI irritation
• Peptic ulceration
• Haemorrhage
• Bronchospasm
• Tinnitus (regular high dose)
• Life-threatening in overdose.
  
  • hyperventilation
  • hearing changes
  • metabolic acidosis
  • confusion
  • convulusions
  • cardiovascular collapse
  • respiratory arrest

Question 4

Warnings of aspirin?

Answer 4

Avoid in:
- children <16 years (risk of Reye’s syndrome affects liver and brain)
- aspirin/NSAID hypersensitivity patients who have bronchospasm or other allergic symptoms triggered
- third trimester pregnancy -prostaglandin inhibition can lead to premature closure of the ductus arteriosus

Caution in:
- peptic ulcer (+PPI)
- gout (may trigger acute attack)

Question 5

Interactions of aspirin?

Answer 5

• Increased risk of bleeding as aspirin acts synergistically with other antiplatelet agents.
• Caution required when giving aspirin alongside antiplatelet drugs and anticoagulants.

Question 6

Monitoring of aspirin?

Answer 6

Ask about side effects.

Question 7

Pt education of aspirin?

Answer 7

Aims to prevent heart attacks or stroke, prolongs life.

Warn about indigestion or bleeding symptoms and report to doctor if they occur.

Take med after food.

Question 8

Indications of antiplatelet drugs?

Answer 8

ACS & Acute ischaemic stroke

Coronary artery stents

Cardiovascular, cerebrovascular, and peripheral arterial disease

Question 9

MOA of antiplatelet drugs?

Answer 9

Antiplatelet drugs prevent platelet aggregation and the risk of arterial blockage by binding irreversibly to adenosine diphosphate (ADP) receptors on the surface of the platelets.

Question 10

Adverse effects of antiplatelet drugs?

Answer 10

• GI upset
  
  • dyspepsia
  • abdominal pain
  • diarrhoea
• Bleeding
• Thrombocytopenia

Question 11

Warnings of antiplatelet drugs?

Answer 11

Avoid in:
- significant active bleeding
- elective surgery, stop 7 days before surgery

Caution in:
- renal and hepatic impairment.

Question 12

Interactions of antiplatelet drugs?

Answer 12

CLOPIDOGREL:
- Efficacy may be reduced by CYP inhibitors.
- Prescribe with lansoprazole or pantroprazole, not omeprazole.

PRASUGREL:
- no interaction

TICAGRELOR
- interacts with CYP inducers/inhibitors, NSAIDs, and anticoagulants -increase risk of bleeding.

Question 13

Monitoring of antiplatelet drugs?

Answer 13

Monitor side effects.

Question 14

Pt education of antiplatelet drugs?

Answer 14

Aim to reduce the risks of heart attacks or strokes and to prolong life.

Continue treatment as advised, usually for 12 months, following drug-eluting stent to ensure the stent stays open and does not block and cause a heart attack.

Check patient is not actively bleeding before treatment.
- If bleeding during treatment, it might take longer for the bleed to stop.

Report unusual bleeding to the doctor.