Anti-Thrombotics

Question 1

3 classes of drugs

Answer 1

Anti-coagulants
Anti-platelet
Thrombolytic Agents

Question 2

Anti-coagulants Drugs

Answer 2

Heparin
LMWH
Warfarin

Question 3

LMWH vs Heparin

Answer 3

LMWH: Longer F, longer t1/2

Question 4

Heparins MOA

Answer 4

Bind tightly to AT III, cause conformation change
To inhibit thrombin, must bind to AT III & thrombin
To inhibit factor X, need to bind to AT III only
LMWH increase action of AT III on factor Xa, but not on thrombin

Question 5

Heparins Route of Administration

Answer 5

Give IV/SubQ
(if give IM - form haematomas)

Question 6

Heparin ADR

Answer 6

Haemorrhage: stop heparin therapy, give protamine sulfate

Thrombocytopenia: heparin binds to platelet 4, autoantibody generated to target complex

Question 7

Heparin & Warfarin Uses

Answer 7

Treat DVT, PE, acute MI
Can be used with thrombolytics for revascularization, with GP IIb/IIIa inhibitors during angioplasty & placement of coronary stents

Heparin: Use in pregnancy
Warfarin: CANNOT use in pregnancy

Question 8

Warfarin PK

Answer 8

Oral - absorbed quickly & totally
Small Vd (>99% bound to plasma albumin)
E dependent on M by P450

Question 9

Warfarin ADR

Answer 9

Bleeding
Not used in pregnancy: cross placenta, cause hemorrhagic disorder in fetus, fetal proteins with gamma-carboxyglutamate residues found in bone & blood may be affected by warfarin

Question 10

Anti-platelet Drug classes (4)

Answer 10

NSAID: Aspirin
ADP receptor blockers: Clopidogral, Ticlopidine, Dipyridamole
GP IIb/IIIa antagonist: Abciximab, Eptifibatide, Tirofiban
PDE Inhibitor: Dipyridamole

Question 11

Aspirin PK

Answer 11

Inhibitory effect rapid, last for platelet life (~7-10 days)

Question 12

Aspirin Uses

Answer 12

Prophylactic treatment of transient cerebral ischemia
Lower incidence of recurrent MI
Decrease mortality in post MI patients

Question 13

Aspirin ADR

Answer 13

Bleeding (PGI2)
Gastric upset & ulcers (PGE2)

Question 14

GP IIb/IIIa receptor Function

Answer 14

Receptor for fibrinogen & vitronectin
Complex is final common pathway for platelet aggregation

Question 15

GP IIb/IIIa Blockers MOA

Answer 15

Inhibit binding of fibrinogen & other ligands to GP IIb/IIIa

Question 16

ADP Receptor Blocker MOA

Answer 16

Block binding of ADP to ADP receptor

Question 17

PDE blocker MOA

Answer 17

Block cAMP from being converted to 5’-AMP

Question 18

Thrombolytic Agents Drugs (4)

Answer 18

Tissue plasminogen Activator (t-PA)
Urokinase
Streptokinase
Anistreplase

(don’t write t-PA & urokinase together in exam)

Question 19

Fibrinolytic Agents MOA

Answer 19

Increase conversion of plasminogen to plasmin, increased formation of fibrin degradation product

Question 20

Fibrinolytic Agents Uses

Answer 20

Emergency treatment of coronary artery thrombosis
Peripheral arterial thrombosis & emboli
Ischaemic stroke (<4.5h window)

Question 21

Fibrinolytic Agents PK

Answer 21

Intracoronary injection, IV injection

Question 22

Fibrinolytic Agents ADR

Answer 22

Bleeding
Contraindication: wound healing, pregnancy