Anti-platelets

Question 1

MoA of Antiplatelets and Fibrinolytics

Answer 1

Anti-platelets –> decrease Platelet aggregation
Fibrinolytics –>Fibrinolysis (fibrin removal)

Question 2

Anti-platelet drugs

Answer 2

1) Asprin
2) Adenosin (P2Y12) receptor Antagonist
3) Dipyridamole
4) Glycoprotein IIB/IIA receptor antagonist
5) others: Epoprostenol (PGI2)

Question 3

Fibrinolytic drugs

Answer 3

1) Streptokinase
2) tPA- Recombinant tissue plasminogen activators

Question 4

Anti-fibrinolytic drugs?

Answer 4

Tranexamic Acid

Question 5

MoA of Aspirin

Answer 5

Ireversible inhibition of COX-1 –> inhibits platelet TXA2 synthesis

Question 6

Clinical uses of Aspirin

Answer 6

Main Antiplatlet drug
–> used in Throbotic stroke/ MI

Question 7

Administration of Aspirin

Answer 7

Oral

Note:
Acute Administartion in Thrombotic stroke/MI –> Single dose of 300mg to achive rapid inhibition of TXA2 then switched to daily dose of 75mg

Question 8

AE of Aspirin

Answer 8

1) Gastric ulcer
2) Allergic rxn ( in Asthmatics)
3) Reye’s Syn. in children
4) Tinnitus, vertigo , nausea
5) increased risk of bleeding

Question 9

Adenosin (P2Y12) receptor Antagonists examples

Answer 9

Clopidogrel
Prasugrel
Ticagrecol

-grel

Question 10

Irreversible inhibitors of P2Y12 receptors

Answer 10

Clopidogrel , Prasugrel

Question 11

Reversible, Non-competitive inhibitor of P2Y12 receptor

Answer 11

Ticagrecol

Question 12

what hepatic enzyme is responsible for the metabolism of Clopidegrol

Answer 12

CYP2C19

Question 13

**

Clinical uses of Clopidogrel

* irreversible inhibitor of (P2Y12) Receptros

Answer 13

Added to Aspirin in:
Unstable coronary syndromes (Unstable angina / MI)

Question 14

Contraindications of Clopidogrel

Answer 14

w/ PPIs (e.g., Omeprazole) –> Drug-Drug interactions since it is matabolized by CYP2C19

Question 15

What hepatic enzymes metabolize Prasugrel and Ticagrecol?

Answer 15

CYP450

Question 16

AE of Adenosine (P2Y12) receptor Antagonists

Answer 16

1) Bleeding (increased risk of hemorrhage)
2) Dyspepsia
3) Diarrhoea
4) Rash
5) Angiodema
6) Dyspnea

Question 17

MoA of Dipyridamole

Answer 17

Inhibits platelet aggregation by several mechanisms
* Inhibition of phosphodiesterase (PDE)
* Blockade of adenosine uptake
* Inhibition of TXA2 synthesis

Question 18

**

Clinical uses of Dipyridamole

Answer 18

added in combo w/ Asprin in :
Transinet cerebral ischemic attack (‘ministroke’) or thrombotic stroke, to prevent recurrence

Question 19

AE of Dipyridamole

Answer 19

• Dizziness, headache and GI disturbances
• Unlike aspirin, it does not increase risk of bleeding

Question 20

Glycoprotein IIB/IIA receptor Antagonist examples

Answer 20

1) Abciximab (IV)
2) Tirofiban (IV)
3) Eptifibatide (IV)

Question 21

Clinical uses of Tirofiban, Eptifibatide and Abciximab

Answer 21

• Reduce early events in acute coronary syndrome
• high-risk patients undergoing coronary angioplasty

Question 22

AE of GP IIB/IIA receptor antagonist

Answer 22

1) Increase the risk of bleeding
2) May cause thrombocytopenia

Question 23

MoA of Epoprostenol

Answer 23

Agonist at Protanoid IP receptors:
vasodilators and platelet-aggregation inhibitors

Question 24

Clinical uses of Epoprostenol (PGI2)

Answer 24

1) Heamodialysis –> to prevent thrombosis
2) Severe Pulmonary HTN
3) Circulatory failure

Question 25

AE of Epoprostenol (PGI2)

Answer 25

flushing, headache, hypotension

Question 26

MoA of Fibrinolytics

Answer 26

Conversion of Plasminogen –> plasmin –> cleaves thrombin and fibrin clots

																																																														"Fibrinolysis (removal of fibrin)"

Question 27

MoA of Streptokinase

Answer 27

Plasminogen activator

Question 28

Administration of Streptokinase

Answer 28

IV

Question 29

Clinical uses of tPA (Alteplase)

Answer 29

• Acute MI w/ ST sgement elevation on the ECG within 12h of onset (the earlier the better!!)
• Acute thrombotic stroke within 3h of onset

Question 30

MoA of Ateplase, Duteplase, Reteplase

Answer 30

More active on fibrin-bound plasminogen than on plasma plasminogen: ‘clot selective’

Question 31

Administration of Ateplase, Duteplase, Reteplase

Answer 31

IV infusion

Question 32

Recombinant tPA (tissue plasminogen activator)

Answer 32

Ateplase,
Duteplase,
Reteplase

Question 33

Clinical uses of Streptokinase

Answer 33

reduces mortalitiy in Acute MI, additive beneficial effects w/ Aspirin

Question 34

what Fibrinolytic drug is characterised by Action block by Abs 4 days or more after the initial dose?

Answer 34

Streoptokinase
(thefore, it should not be repeated after this time has elapsed)

Question 35

AE of tPA drugs?

Answer 35

Bleeding
- GI haemorrhage and haemorrhagic stroke

Question 36

What agent is used to reverse bleeding caused by Atleplase (and other pTA)?

Answer 36

1) Tranexamic acid
2) free fresh plasma
3) Couagulation factor
4) Aminocaproid

Question 37

AE of Streptokinase?

Answer 37

1) Allergic rxn
2) low-grade fever
3) hypotension

Question 38

MoA of Tranexamic acid

Answer 38

Inhibits plasminogen activation –>Prevents fibrinolysis

Question 39

Administration of Tranexamic acid

Answer 39

IV /Oral

Question 40

Clinical uses of Tranexamic acid

Answer 40

Used to treat various conditions in which there is
bleeding or risk of bleeding:
1) Haemorrhage following prostatectomy or dental extraction
2) Menorrhagia(excessive menstrual blood loss)
3) Life threatening bleeding following thrombolytic drug administration (tPAs)