CV Anti-platelet and Anti-coagulants

Question 1

Aspirin

Answer 1

treats unstable angina. permanently acetylates Cox1, blocks synthesis thromboxane A2. decrease platelet aggregation. reduce MI + death incidence in patients w/ unstable angina by >50%. reduce MI in patients with exertional angina. low oral dose preferable. Adverse bleeding. well tolerated, some exhibit resistance to anti-platelet effect

Question 2

ADP Inhibitors

Answer 2

treats unstable angina. inhibits binding ADP to platelets, decreases platelet aggregation. early initiation - improved outcomes, 20-35% reduction MI + death. oral slow onset, long duration, can be used in place of aspirin. well tolerated. Adverse neutropenia and bleeding. some show resistance

Question 3

GP IIb/IIIa R inhibitors

Answer 3

treats unstable angina. prevent fibrinogen cross linkage, decrease aggregation. early initiation - better outcomes, 9% reduction MI + death. Adm. IV, short duration. oral ineffective. used with aspirin/heparin. Adverse substantial bleeding, thrombocytopenia. effectively used prior to percutaneous coronary intervention

Question 4

Heparin (unfractionated or LMWH)

Answer 4

treats unstable angina. catalyzes inhibition of coagulation proteases by anti-thrombin. LMWH greater reduction in death + MI, combine with aspirin. Adm. Heparin - IV, LMWH - subQ. Adverse substantial bleeding, thrombocytopenia. resistance to heparin can occur but not with LMWH

Question 5

Fondaparinux

Answer 5

treats unstable angina. synthetic binds to antithrombin, inhibits factor Xa. reduces MI + death similar to heparin. 100% bioavailability subQ, long half life, once daily anticoagulation w/o monitoring. Adverse bleeding

Question 6

Direct Thrombin Inhibitors

Answer 6

leech based, bind to catalytic site of thrombin. produce stable anticoagulation but not proven to treat unstable angina. Adm. IV, used in place of heparin in patients prone to thrombocytopenia. Adverse bleeding

Question 7

Oral Anti-coagulatants (Warfarin)

Answer 7

prevent 2° MI. block synthesis reduced Vitamin K. decrease growth of thrombi, prevent new thrombi. Onset over days, intensity monitored w/ prothrombin time. Adverse bleeding common, many drug interactions

Question 8

Dabigatran

Answer 8

prevent 2° MI. reversibly blocks active site of thrombin. rapid onset. decrease growth of thrombi, prevent new thrombi. fixed oral dose gives predictable anti-coagulant response. only for preventing stroke in A-fib. Adverse bleeding less than warfarin. few drug interactions