AFRM Module 2 – Pharmacology Sample Questions
Solved 100% Correct
Aspirin - MOA
1.1 Irreversibly inhibits cyclo-oxygenase COX-1 and COX-2 (but weakly more selective for COX-
1)
1.2 Suppress production of prostaglandin and thromboxane A2
1.3 inhibits platelet aggregation
Clopidogrel - MOA
Prodrug that irreversibly inhibits P2Y12 ADP-mediated platelet activation and aggregation
Ticagrelor - MOA
reversible and noncompetitive binder of the adenosine diphosphate (ADP) P2Y12 receptor on
the platelet surface which prevents ADP-mediated activation of the GPIIb/IIIa receptor complex
thereby reducing platelet aggregation.
Heparin / LMWH (e.g. Enoxaparin) - MOA
Inactivates Factor Xa and inhibits conversion of prothrombin to thrombin (IIa)
LMWHs and danaparoid have greater effect on factor Xa > thrombin
Heparins - important side effects
Bleeding, bruising
Mild reversible thrombocytopaenia
Transient ALT/AST rise
HIIT (immune mediated) <1% (within 5-10 days) (use danaparoid instead)
Dabigatran - MOA
,competitive, reversible, direct thrombin inhibitor. Because thrombin enables the conversion of
fibrinogen into fibrin during the coagulation cascade, its inhibition prevents the development of
a thrombus. Both free and clot-bound thrombin and thrombin-induced platelet aggregation are
inhibited.
DOACs - important side effects
Bleeding
Gastritis, dyspepsia, GI bleed
Oesophageal ulcers
Increase liver enzymes, bilirubin
Anticoagulant-related nephropathy
DOAC / FXa inhibitor - MOA
Inhibit Xa > blocks thrombin production > blocks conversion of fibrinogen to fibrin > inhibit
thrombus development
FXai - reversal agent?
Dabigatran - reversal agent?
Heparin - reversal agent?
FXai = andexanet alfa
- Inactive form of human factor Xa that binds to apixaban or rivaroxaban, reduce capacity to act
on endogenous Xa
Dabigatran (direct thrombin inhibitor) = Idarucizumab
- Humanised monoclonal antibody fragment (Fab) à binds with dabigatran and its metabolites à
form a stable inactive complex
Heparin = protamine
- Combines with heparin to form a stable inactive complex, reversing its anticoagulant effect
, - re-heparinisation may not be effective until the protamine has been eliminated. Guided by
monitoring the APTT every 20-30 minutes post
Warfarin - MOA
Vit K antagonist
Inhibits vitamin K epoxide reductase
Inhibit synthesis of vit K-dependent factors (2, 7, 9, 10), and antithrombotic factors protein C
and protein S
DOAC contraindications / Warfarin indications
Valvular AF
Mechanical / Prosthetic heart valves
Rheumatic mitral stenosis
Renal impairment:
- Apixaban eGFR <25
- Rivaroxaban <15
- Dabigatran <30
Triple positive aPLS
How long to withhold anticoagulation for (elective) surgery? (DOAC vs warfarin)
DOAC
- stop 1 day (low risk) / 2-3 days before surgery (high risk)
- restart 1 day (low risk) / 2-3 days post-surgery (high risk bleed).
Warfarin =
- stop 4-5 days (to drop INR<1.5), consider bridging heparin
- usually can restart on same night of surgery
Tissue plasminogen activator (e.g. alteplase, tenecteplase) - MOA, indications
Solved 100% Correct
Aspirin - MOA
1.1 Irreversibly inhibits cyclo-oxygenase COX-1 and COX-2 (but weakly more selective for COX-
1)
1.2 Suppress production of prostaglandin and thromboxane A2
1.3 inhibits platelet aggregation
Clopidogrel - MOA
Prodrug that irreversibly inhibits P2Y12 ADP-mediated platelet activation and aggregation
Ticagrelor - MOA
reversible and noncompetitive binder of the adenosine diphosphate (ADP) P2Y12 receptor on
the platelet surface which prevents ADP-mediated activation of the GPIIb/IIIa receptor complex
thereby reducing platelet aggregation.
Heparin / LMWH (e.g. Enoxaparin) - MOA
Inactivates Factor Xa and inhibits conversion of prothrombin to thrombin (IIa)
LMWHs and danaparoid have greater effect on factor Xa > thrombin
Heparins - important side effects
Bleeding, bruising
Mild reversible thrombocytopaenia
Transient ALT/AST rise
HIIT (immune mediated) <1% (within 5-10 days) (use danaparoid instead)
Dabigatran - MOA
,competitive, reversible, direct thrombin inhibitor. Because thrombin enables the conversion of
fibrinogen into fibrin during the coagulation cascade, its inhibition prevents the development of
a thrombus. Both free and clot-bound thrombin and thrombin-induced platelet aggregation are
inhibited.
DOACs - important side effects
Bleeding
Gastritis, dyspepsia, GI bleed
Oesophageal ulcers
Increase liver enzymes, bilirubin
Anticoagulant-related nephropathy
DOAC / FXa inhibitor - MOA
Inhibit Xa > blocks thrombin production > blocks conversion of fibrinogen to fibrin > inhibit
thrombus development
FXai - reversal agent?
Dabigatran - reversal agent?
Heparin - reversal agent?
FXai = andexanet alfa
- Inactive form of human factor Xa that binds to apixaban or rivaroxaban, reduce capacity to act
on endogenous Xa
Dabigatran (direct thrombin inhibitor) = Idarucizumab
- Humanised monoclonal antibody fragment (Fab) à binds with dabigatran and its metabolites à
form a stable inactive complex
Heparin = protamine
- Combines with heparin to form a stable inactive complex, reversing its anticoagulant effect
, - re-heparinisation may not be effective until the protamine has been eliminated. Guided by
monitoring the APTT every 20-30 minutes post
Warfarin - MOA
Vit K antagonist
Inhibits vitamin K epoxide reductase
Inhibit synthesis of vit K-dependent factors (2, 7, 9, 10), and antithrombotic factors protein C
and protein S
DOAC contraindications / Warfarin indications
Valvular AF
Mechanical / Prosthetic heart valves
Rheumatic mitral stenosis
Renal impairment:
- Apixaban eGFR <25
- Rivaroxaban <15
- Dabigatran <30
Triple positive aPLS
How long to withhold anticoagulation for (elective) surgery? (DOAC vs warfarin)
DOAC
- stop 1 day (low risk) / 2-3 days before surgery (high risk)
- restart 1 day (low risk) / 2-3 days post-surgery (high risk bleed).
Warfarin =
- stop 4-5 days (to drop INR<1.5), consider bridging heparin
- usually can restart on same night of surgery
Tissue plasminogen activator (e.g. alteplase, tenecteplase) - MOA, indications
