antiplatelets (aspirin)

Question 1

Indication?

Answer 1

cardiovascular disease (secondary prevention); unstable angina; transient ischaemic attack; coronary bypass surgery; drugs used to affect blood coagulation.

Question 2

contraindications?

Answer 2

active peptic ulceration, bleeding disorders (antiplatelet dose); children under 16 (reyes syndrome), haemophilia, previous peptic ulceration, severe cardiac failure for analgesic dose

Question 3

mechanism of action of aspirin?

Answer 3

antiplatelet drug. It inhibits the production of thromboxane A2 (TXA2); a prostaglandin family mediator that is produced in inflammation. Activated platelets produce thromboxane, increase increases the production of GbIIb/ IIa receptors that bind to fibrin and form the clot. TXA2 is produced from arachidonic acid by an enzyme called cyclooxygenase 1 (COX-1). Aspirin irreversibly binds to COX-1. Inhibiting its action and prevents the platelets from producing thromboxane. As thromboxane produces the receptors that bins to fibirin to form the clot, no clot can be formed.

Question 4

side effects?

Answer 4

haemorrhage, bruising, nose bleeds, gastric irritation.

Question 5

how do all platlet drugs work?

Answer 5

inhibiting platelet aggregation along the different pathway and they are grouped according to their mechanism of action. In relation to aspirin- inhibits cycloxygenase.