Block 2 - Antiplatelets Med Chem Flashcards

1
Q

What are the anti platelet drugs?

A
  1. Aspirin
  2. Glycoprotein IIb/IIIa inhibitors
  3. ADP inhibitors (clopidogrel)
  4. PDE/adenosine uptake inhibitors
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Describe how platelet aggregation occurs?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Understand platelet aggregation cascade Slides 5-8

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the MOA of COX1 inhibitors?

A

Block the synthesis of thromboxane A2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is thromboxane A2?

A

key inducer of platelet aggregation → a potent vasoconstrictors at high concentration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Describe the effects of acetylsalicylic acid?

A

Aspirin is an Irreversible inhibitor of COX-1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What gives aspirin is lasting aggregation effect?

A

Lifetime of the platelet and platelets can replicate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are PDE inhibitors do?

A

Leads to increased cAMP leads to negative effect on intracellular calcium levels → drug inhibits → Low intracellular calcium levels inhibit aggregation

Promotes the conversion of cAMP → AMP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the PDE3 inhibitors for platelet aggregation?

A
  1. Dipyridamole
  2. Cilostazol (more selective)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What do PDE3 inhibitors need to mimic?

A

cAMP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the MOA of P2Y purinergic receptor?

A

Targets P2Y12 that promotes ADP binding → intracellular Ca2+

Antagonists → slow activation GP IIb/IIIa receptors → prevents aggregation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the SAR of P2Y antagonists?

A

ADP mimicry

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the ADP binding sites on platelets? Function?

A

Px1, P2Y1, P2Y12

Increases intracellular Ca2+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are P2Y antagonists? Which are prodrugs?

A
  1. Ticlopidine
  2. Clopidogrel
  3. Prasugrel
  4. Ticagrelor (Not prodrug)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What P2Y antagonists are metabolized by CYP?

A
  1. Clopidogrel
  2. Ticagrelor
  3. Ticlopidine

CYP2C19

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Brand name Ticagrelor

A

Brilinta

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the newest anti platelet aggregators?

A

Glycoprotein IIb/IIIa Receptor Antagonists

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

MOA of Glycoprotein IIb/IIIa Receptor Antagonists?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are the benefits of using Glycoprotein IIb/IIIa Receptor Antagonists?

A

provides anti-aggregation regardless of the source of thrombus

20
Q

What are the peptide sequences of Glycoprotein IIb/IIIa Receptor Antagonists?

A

Arg-Gly-Asp
Lys-Gly-Asp

21
Q

What does Glycoprotein IIb/IIIa Receptor Antagonists mimic?

A

disintegrin

22
Q

What is abciximab? ADR?

A
  1. Chimeric murine antibody (contains Arg-Gly-Asp)
  2. Long DOA
  3. Peptide

Thrombocytopenia

23
Q

What is Eptifibatide? ADRs?

A

Cylic heptapeptide containing Lys-Gly-Asp

Highly specific with low binding affinity (peptide)

Advantage b/c highly reversible = less thrombocytopenia

24
Q

What is tirofiban

A
  1. Disimalr to disinterring (isolated from snake venom)
  2. Peptidomimetic (COOH and NH mimic the Arg-Gly-Asp of disintegrin)

Better bioavailability

25
Q

What is desmopressin (DDVAP)?

A
  1. Vasopressin analogue
  2. Increase the release of Von Willebrand factor → increase platelet adhesion
  3. Same indication as vasopressin
26
Q

Why does vasopressin have to be given as an injection?

A

Peptide

27
Q

What are the indications of vasopressin?

A

central diabetes insipidus: extreme urination, thirst, bed-wetting

Better than desmopressin

28
Q

MOA of vasopressin?

A

Increases release of von Willebrand factor

29
Q

Why is DDAVP have better PO bioavailability the vasopressin?

A

Formas a more acid stable structure → deaminated Cys and altered stereochemistry in Arg

30
Q

What is von Willebrand factor?

A

Increases the amount of stickiness of platelets → Increases platelet binding

31
Q

What are classes of thrombolytics?

A
  1. t-Pa derivatives
  2. Streptokinase
32
Q

What is the MOA of thrombolytics?

A
  1. Dissolves clots that have formed
  2. Activates plasminogen to plasmin conversion → Degradation of fibrin
33
Q

Describe the conversion of plasminogen to plasmin

A
34
Q

What is the exception of urokinase?

A
  1. Plasminogen to plasmin conversion
  2. Degrades fibrin directly
35
Q

What are thrombolytics IV?

A
  1. peptidic in nature
  2. Based on tPA
  3. Occurs naturally in body, regulated by tPA1 and tPA2
36
Q

What is streptokinase?

A
  1. No activity until bound to plasminogen (1:1)
  2. breaks down fibrinogen, factor V, VII
  3. Drug of choice (cheap and effective)
37
Q

What is the ADR of streptase?

A

Activates immune system

Comes from streptococcus

38
Q

MOA of urokinase?

A

Kinlytic
1. isolated from urine (hence the name) but now from cultured human fetal kidney cells
2. Same MOA + breaks down fibrin directly
3. Short half-life
4. No hypersensitivity

39
Q

What is alteplase?

A

Low affinity for free plasminogen, high affinity for plasminogen bound to fibrin in a thrombus

Ultra short DOA

From isolated human melanoma cells

Expensive

40
Q

What are the types of thrombolytics?

A
  1. Streptase (Streptokinase)
  2. Kinlytic (Urokinase)
  3. Activase (Alteplase)
  4. Retevase (Reteplase)
  5. TNKase (Tenecteplase)
41
Q

What is Retevase (Reteplase)?

A

525 amino acid sequence of Alteplase w/o the first 172 amino acids

Same MOA but more specific than Alteplase

42
Q

How does Tenecteplase differ from Alteprase?

A
  1. 3 point mutation
  2. 15x more specific
  3. 80x more potent
43
Q

What are the plasminogen-based reversal agents?

A

Lysteda (tranexamic acid)

44
Q

MOA of Lysteda?

A
  1. Inhibitor of fibrinolysis (“anti-fibrinolytic” or “anti-thrombolytic”)
  2. Synthetic lysine analogue
  3. Same MOA for aminocaproic acid
45
Q

Indications of Lysteda?

A
  1. Does not increase clotting, but rather stabilizes existing clots
  2. Denistry
  3. CO formulated with mefanamic acid (NSAID) for decrease of pain and blood loss with menorrhagia