Pharmacology - Procoagulant, Anticoagulant, and Thrombolytic Drugs (Exam 3)

Question 1

Serotonin is taken up from the circulation and stored in
platelets. Which statement best describes the role of
serotonin in platelet activation?

(a) Serotonin is a strong platelet agonist similar to ADP, collagen, and norepinephrine.

(b) Platelets act as a storage depot for serotonin but serotonin has no role in platelet activation or aggregation.

(c) Selective serotonin reuptake inhibitors increase serotonin storage in platelets.

(d) Serotonin synergistically potentiates platelet activation by stronger agonists including ADP, collagen, and norepinephrine.

(e) Serotonin reduces platelet activation by strong agonists including ADP, collagen, and norepinephrine

Answer 1

(d) Serotonin synergistically potentiates platelet activation by stronger agonists including ADP, collagen, and norepinephrine.

Question 2

Which is the preferred intrasocket preparation to
promote local hemostasis by significantly activating
platelets during dental procedures?

(a) platelets
(b) silver
(c) gelatin
(d) collagen
(e) cellulose

Answer 2

(d) collagen

Question 3

Which of the following platelet receptors is a drug
target for anti-platelet therapy and facilitates platelet crosslinking through formation of fibrin strands?

(a) COX-1
(b) GP IIb-IIIa
(c) P2Y12
(d) PAR1
(e) GP Ia-IIa

Answer 3

(b) GP IIb-IIIa

Question 4

Unfractionated heparin and low molecular weight heparins (LMWHs) such as enoxaparin differ in their ability to inhibit coagulation factors Xa and IIa (thrombin). Which statement best describes this difference?

(a) LMWHs preferentially associate with antithrombin III to form a complex with factor Xa to inactivate Xa but minimally inhibit factor IIa resulting in anti-Xa/anti-IIa activity ratios greater than 1.

(b) LMWHs preferentially associate with antithrombin III to form a complex with factor Xa to inactivate Xa but minimally inhibit factor IIa resulting in anti-Xa/anti-IIa activity ratios less than 1.

(c) LMWHs preferentially associate with antithrombin III to form a complex with factor Xa to inactivate Xa and factor IIa resulting in
an anti-Xa/anti-IIa activity ratio of 1:1.

(d) LMWHs preferentially associate with antithrombin III to form a complex with factor IIa to inactivate IIa but not Xa.

(e) Unlike unfractionated heparin, LMWHs do not have to associate with antithrombin III to inhibit factor Xa.

Answer 4

(a) LMWHs preferentially associate with antithrombin III to form a complex with factor Xa to inactivate Xa but minimally inhibit factor IIa resulting in anti-Xa/anti-IIa activity ratios greater than 1.

Question 5

Warfarin is a very powerful anticoagulant that is used to maintain anticoagulation in patients with prosthetic
heart valves. Because of the potential for warfarin to
result in excess dangerous anticoagulation, dosing is
monitored and adjusted based on the international
normalization ratio (INR).

The INR is based on patient
coagulation testing. What common coagulation test is
used to calculate the INR?

(a) thrombin time (TT)
(b) anti-Xa assay
(c) activated partial thromboplastin time (aPTT)
(d) platelet aggregation test (PAT)
(e) prothrombin time (PT)

Answer 5

(e) prothrombin time (PT)

Question 6

Warfarin inhibits the reduction of vitamin K.

Vitamin K is required for the production of which clotting factors in the liver?

(a) Factors II, V, IX, and X
(b) Factors I, II, V and VIII
(c) Factors II, VII, IX and X
(d) Factors X, XI, XII and XIII
(e) Factors V, VII, VIII and IX

Answer 6

(c) Factors II, VII, IX and X

Question 7

Which statement best describes the mechanisms of action of thrombolytics such as tissue plasminogen activator (tPA), and antithrombolytics such as aminocaproic acid (ACA)?

(a) tPA converts plasminogen to plasmin which proteolyzes fibrin to break down blood clots, whereas ACA inhibits the conversion of plasminogen to plasmin to maintain fibrin blood clots.

(b) tPA converts plasminogen to plasmin which catalyzes the formation of fibrin blood clots, whereas ACA inhibits the conversion of plasminogen to
plasmin to break down blood clots.

(c) tPA directly proteolyzes fibrin to break down blood clots, whereas ACA
indirectly breaks down blood clots by converting plasminogen to plasmin
which breaks down blood clots.

(d) ACA directly complexes with tPA to inhibit the ability of tPA to breakdown fibrin blood clots.

(e) tPA directly complexes with ACA to inhibit the ability of ACA to maintain
fibrin blood clots.

Answer 7

(a) tPA converts plasminogen to plasmin which proteolyzes fibrin to break down blood clots, whereas ACA inhibits the conversion of plasminogen to plasmin to maintain fibrin blood clots.

Question 8

Which drug is recommended as first-line antiplatelet therapy?

(a) heparin
(b) warfarin
(c) aspirin
(d) ibuprofen
(e) tissue plasminogen activator

Answer 8

(c) aspirin

Question 9

What is the target INR for dental procedures expected
to result in significant bleeding?

(a) < 4
(b) > 2
(c) > 1
(d) > 3
(e) < 3

Answer 9

(e) < 3

Question 10

What statement best describes the use of antiplatelet medications
with anticoagulants?

(a) Simultaneous use of antiplatelet medications with anticoagulants is
necessary to achieve sustainable anticoagulation.

(b) Antiplatelet medications are never used with anticoagulants.

(c) Antiplatelet medications such as aspirin are preferred over anticoagulants such as warfarin in patients with native valvular heart disease and atrial fibrillation.

(d) Simultaneous use of antiplatelet drugs with anticoagulants should be
minimized to prevent the risk of excessive bleeding.

(e) When the antiplatelet drug aspirin is used with heparin anticoagulant,
the dose of aspirin must be increased to prevent heparin induced
thrombocytopenia (decreased platelets).

Answer 10

(d) Simultaneous use of antiplatelet drugs with anticoagulants should be
minimized to prevent the risk of excessive bleeding.