Clinical Pharmacology of Acute coronary syndrome

Question 1

What are the different ACS

Answer 1

Unstable angina
NSTEMI
STEMI

Question 2

How is myocardial O2 supply increased in unstable angina and NSTEMI

Answer 2

Coronary vasodilation
Correct hypoxaemia
Stop platelet aggregation
Stop progression to STEMI

Question 3

How is myocardial oxygen demand decreased

Answer 3

Reduce heart rate
Reduce blood pressure (afterload)
Reduce preload
Reduce contractility and wall stress

Question 4

What is the initial management

Answer 4

M - Morphine
O – Oxygen
N - Nitrates
A - Aspirin
C/T/P - Clopidogrel/Ticagrelor/Prasugrel
+ Fondaparinux (OASIS-6 trial)

Question 5

What is used to decrease myocardial oxygen demand

Answer 5

Bisoprolol (beta blocker)
Nitrates (not calcium channel blockers)
Ramipril (ace inhibitor)
Atorvastatin

Question 6

What is the effect of aspirin

Answer 6

Thromboxane-A2 inhibitor
Inhibit platelet activation and recruitment

Question 7

What is the effect of Clopidogrel/Ticagrelor/Prasugrel

Answer 7

Inhibits ADP activation of P2Y12 receptor

Question 8

What is the effect of Fondaparinux

Answer 8

Synthetic pentasaccharide
Causes less clots:

(Binds to antithrombin III and potentiatesFactor Xa inhibition x300. Neutralization of Factor Xa decreases the conversion of prothrombin to thrombin, which subsequently decreases the conversion of fibrinogen to fibrin)

Question 9

What are the goals for treatment of STEMI

Answer 9

Unblock the artery
* Vasodilators don’t work
* Stop platelet aggregation
* Emergency angioplasty
* If angioplasty not available -Thrombolysis

Question 10

When is thrombolysis used

Answer 10

invasive procedure not available within 120 minutes

Question 11

How does recombinant tissue plasminogen activator work

Answer 11

Converts plasminogen to plamin
Plasmin lyses clot, breaks down fibrinogen and fibrin

Question 12

What is the funtion of fibrin specific agents

Answer 12

Catalyse conversion of plasminogen to plamin in absence of fibrin
* Alteplase
* Tenecteplase - (mutated alteplase, higher fibrin specificity and longer half-life)

Question 13

What is the function of non-fibrin specific agents

Answer 13

Catalyse systemic fibrinolysis
* Steptokinase - Lower efficacy but lower bleeding risk

Question 14

What are the thrombolysis contraindications

Answer 14

Prior intracranial haemorrhage
Known intracranial lesion
Ischaemic stroke within 3 months
Suspected aortic dissection
Active bleeding
Significant closed head trauma (<3 months)

Question 15

What are the benefits of thrombolysis

Answer 15

23% reduction in mortality
39% reduction when used with Aspirin (ISIS-3 trial)
Ability to use haemodynamic support
* Intra-aortic balloon pump
* Impella device
* Emergency surgery

Question 16

What is the drawback of thrombolysis

Answer 16

Invasive management more effective – 7% reduced mortality in high risk cases