From Jen: Heme

Question 1

Heparin

Answer 1

MOA: catalyzes activation of antithrombin III: ↓ thrombin and Xa
short half life

Use: PE, stroke, acute coronary syndrome, MI, DVT

Ok in pregnancy, does not cross placenta

Follow PTT (intrinsic pathway)

Question 2

Heparin

Toxicity

Answer 2

Bleeding, thrombocytopenia (HIT), osteoporosis, DDI

Antidote: protamine sulfate: positively charged molecule that binds negatively charged heparin

Newer LMWH (enoxaparin) acts more on Xa, has better availability, longer half life. Can be administered subQ and does not require monitoring, not easily reversible

Question 3

Heparin induced thrombocytopenia (HIT)

Answer 3

binds platelets, causing auto Ab production that destroys platelets and activates remaining ones

Results in thrombocytopenic, hypercoagulable state

Question 4

Lepirudin

bivalirudin

Answer 4

Hirudin derivatives: directly inhibit thrombin

Alternative to heparin in pts with HIT syndrome

Question 5

Warfarin

Answer 5

MOA: Interferes with epoxide reductase, which activates Vit K, allowing carboxylation of II, VII, IX, X, Protein C and S

Metabolized by P450

Monitor PT (extrinsic pathway)

Use: Chronic anticoagulation: not in pregnancy

Toxicity: bleeding, teratogenic, skin/tissue necrosis, DDI

Question 6

Warfarin antidote

Answer 6

IV Vit K, fresh frozen plasma

Question 7

Thrombolytics

Answer 7

Streptokinase, urokinase, tPA (alteplase), APSAC (anistreplase)

MOA: aid or directly activate plasminogen to plasmin, which cleaves thrombin AND fibrin clots

↑ PT and PTT, no change in platelet count

Use: early MI or ischemic stroke

Question 8

Thrombolytics

Toxicity

Answer 8

streptokinase, urokinase, tPA (alteplase), APSAC (anistreplase)

bleeding (contraindicated in pts with recent or active bleeding, HTN)

Antidote: aminocaproic acid (inhibitor of fibrinolysis)

Question 9

Aspirin

Answer 9

Irreversibly inhibits COX1 and COX2 to prevent conversion of arachidonic acid to TXA2

↑ bleeding time, no effect on PT/PTT

Use: antipyretic, analgesic, anti-inflammatory, anti-platelet

Toxicity: gastric ulceration, bleeding, hyperventilation, Reye’s syndrome, tinnitus (CN VIII)

Question 10

Clopidogrel

Ticlopidine

Answer 10

MOA: inhibit platelet aggregation by irreversibly blocking ADP receptors. Inhibit fibrinogen binding by preventing GpIIb/IIIa expression

Use: acute coronary syndrome, coronary stenting. ↓ incidence or recurrence of thrombotic stroke

Adverse: neutropenia (ticlopidine)

Question 11

Abciximab

Answer 11

MOA: Monoclonal Ab that binds to the glycoprotein receptor IIb/IIIa on activated platelets, preventing aggregation

Use: acute coronary syndromes, percutaneous coronary angioplasty

Adverse: bleeding, thrombocytopenia