Antiplatelets- aspirin

Question 1

What are common indications?

Answer 1

Acute coronary syndrome and acute iscaemic stroke
secondary prevention of major cardiovascular event
higher dose- mild to moderate pain and fever

Question 2

What is its mechanism of action?

Answer 2

Aspirin irreversibly inhibits COX to reduce production of pro-aggregator factor thromboxane from arachidonic acid, reducing platelet aggregation and the risk of arterial occlusion.

Antiplatelet effect occurs at low doses and last 7-10 days, the effect wears off as new platelets are made

Question 3

What are common side effects?

Answer 3

-GI upset
-peptic ulcers
-haemorrhage
-hypersensitivity
-bronchospasm
Regular high dose- tinnitus

Question 4

ASPIRIN
What are features of overdose?

Answer 4

-hyperventilation
-hearing changes
-metabolic acidosis
-confusion
-convulsions
-cardiovasucular collapse
-respiratory arrest

Question 5

What group of people should NOT be prescribed aspirin and why?

Answer 5

-Asprin should not be given to children younger than 16 due to Reye’s syndrome- rare but life threatening illness that affects the brain and liver.

-women third trimester pregnant

• patients with hypersensitivity i.e who have had bronchospasm/ allergic reaction triggered by exposure to NSAID

Question 6

What are important interactions?

Answer 6

Caution required along side other anticoagulants as can increase risk of bleeding. However it acts synergistically with other agents.

Question 7

What are dosages for each indication?

Answer 7

ACS- loading dose 300mg, followed by regular 75mg dose

Acute ischaemic stroke- 300mg daily for 2 weeks

Long term prevention of thrombosis after acute event- 75mg daily

Pain- 300mg MAX 4g

Question 8

What should be considered to be prescribed along side and to who?

Answer 8

Gastroprotection
those with risk factors:
aged 65>
peptic ulcer previously
co-mordities- CVD disease/diabetes

Question 9

How long is dual antiplatelet therapy used for

Answer 9

usually limited to 12 months so treatment should be reviewed and reduced to single anti platelet drug accordingly

Question 10

When will aspirin be preferred over clopidogrel?

Answer 10

Long-term single anti platelet agent for coronary artery and peripheral vascular disease

Clopidogrel- preferred over a stroke