Session 8 - Anti-platelets, Thrombolysis and IHD

Question 1

What are the two main indications for aspirin?

Answer 1

 Prevention and treatment of MI / Ischaemic stroke

 Analgesic & Anti-inflammatory agent

Question 2

Give five main contraindications for aspirin?

Answer 2

 Children under 12 years who are at risk of Reye’s Syndrome

 Breastfeeding, Haemophilia, peptic ulcers, known hypersensitivity

Question 3

How is aspirin an anti-platelet?

Answer 3

 Prevents the formation of Thromboxane A2 from Arachidonic Acid in platelets. Thromboxane A2 stimulates phospholipase C, increasing calcium levels and causing platelet aggregation

Question 4

Give two aspirin ADRs

Answer 4

 Bronchospasm, GI haemorrhage

Question 5

Give two ways in which aspirin interacts with a particular drug?

Answer 5

 Displaces Warfarin from plasma proteins (PKs)

 Increases Anti-Coagulant effect of Warfarin at a different site (PDs)

Question 6

Give two anti-platelets other than aspirin

Answer 6

Dipyridamole

Copidogrel

Question 7

What is the indication for dipyridamole?

Answer 7

Used in conjunction with warfarin in prophylaxis against thrombosis due to prosthetic mechanical heart valves

Question 8

What is the mech of action of dipyridamole?

Answer 8

 Inhibits Phosphodiesterase enzyme

 Phosphodiesterase increases cAMP, which increases Ca2+, which causes platelet aggregation

Question 9

Give three adverse drug reactions to dipyridamole?

Answer 9

 Hypotension, nausea, diarrhoea, headache

Question 10

What is the main use of clopidogrel?

Answer 10

Can be used if patient allergic to aspirin

Question 11

HOw does clopidogrel work?

Answer 11

 ADP Antagonists

 Inhibits ADP-ADP receptor interaction, which aids platelet aggregation

Question 12

What is glycoprotein IIb and IIIa used for?

Answer 12

 Prevention of ischaemic cardiac complications in patients undergoing Percutaneous Coronary Intervention (PCI)
 Short term prevention of MI in unstable angina patients

Question 13

What is the mech of action of glycoprotein IIb?

Answer 13

 Monoclonal Antibody to Glycoprotein IIb/IIIa Receptors

 Prevents platelet aggregation

Question 14

What is the normal clearance method of fibrin?

Answer 14

Plasmin cleaves fibrin, fibrinogen and other coag factors

Question 15

What is plasmin formed from?

Answer 15

Plasminogen

Question 16

Give two types of fibrinolytic drugs

Answer 16

Ones that generate plasmin themselves (tPA)

Ones that bind to and activate endogenous plasminogen (Streptokinase)

Question 17

Give two fibrinolytics

Answer 17

Streptokinase

Tissue plasminogen activator

Question 18

What is the indication for streptokinase?

Answer 18

 Life-threatening venous thrombosis, pulmonary embolism, arterial thromboembolism, acute myocardial infarction

Question 19

What are the contraindications for streptokinase?

Answer 19

 Recent haemorrhage, trauma, surgery, aortic dissection, coma, history of cerebrovascular disease

Question 20

What does streptokinase do?

Answer 20

Forms a complex with and activates plasminogen -> Plasmin

Question 21

Give three adverse drug reaction of streptokinase

Answer 21

Nausea, vomiting, bleeding/haemorrhage

Question 22

What is streptokiunase often used with?

Answer 22

Anti-platelet and anti-coagulants

Question 23

Why can’t streptokinase be used more than once?

Answer 23

 Streptokinase is derived from haemolytic streptococci, and is therefore antigenic. Repeated administration of streptokinase could therefore result in anaphylaxis.

Question 24

What should streptokinase be replaced by if patient allergic?

Answer 24

Tissue plasminogen activator

Question 25

Give an example of tpaA

Answer 25

 Alteplase

 Reteplase

Question 26

Give two indications for t-PAs

Answer 26

 Myocardial infarction, pulmonary embolism

Question 27

Give some contraindications for tpas

Answer 27

 Recent haemorrhage, trauma, surgery, aortic dissection, coma, history of cerebrovascular disease

Question 28

What do tas do?

Answer 28

 t-PAs are tissue-type plasminogen activators, Plasminogen  Plasmin

Question 29

Give three ADRs for Tpas

Answer 29

 Nausea, vomiting, bleeding/haemorrhage

Question 30

What is acute MI fibrinolysis treatment guideline?

Answer 30

Fibrinolysis should be offered to people with an acute STEMI within 12 hours of onset of symptoms if Percutaneous Coronary Intervention (PCI) cannot be delivered within 120 minutes of the time when fibrinolysis could have been given.

Question 31

How does the window for venous thrombo-embolism compare?

Answer 31

Longer, but only three hours for ischaemic stroke

Question 32

Give three major ADRs of thrombolytic therapy

Answer 32

Bleeding
Anaphylaxis
Hypotension

Question 33

Give 6 major contraindications for fibrinolytic therapy

Answer 33

o Peptic Ulcer (or other potential bleeding source)
o Recent trauma or surgery
o History of cerebral haemorrhage or stroke of uncertain aetiology
o Uncontrolled hypertension
o Coagulation defect
o Previous Streptokinase therapy