Oral Anticoagulants; L2 (9-23-15)

Question 1

Warfarin

• MOA?
• Monitoring?
• Indications?
• Side-effects/toxicity?

Answer 1

• MOA: competitive antagonist of vitamin K; suppresses the synthesis of functional forms of factors II (2), VII (7), IX (9), and X (10)
• Monitoring: prothrombin time/INR
• Indications: prolonged tx of DVT (and PE) and atrial fibrillation (prevention of stroke in AF)

-Side-effects/toxicity: bleeding/HEMORRHAGE (can REVERSE with FFP and vitamin K), coumadin (warfarin) induced necrosis; has interaction with several meds -> results in bleeding due to potentiation of warfarin’s effect
(-Contraindications: bleeding disorders; **PREGNANCY; crosses placenta!!)

Question 2

~Vitamin K

• MOA?
• Monitoring?
• Indications?
• Side-effects/toxicity?

Answer 2

• MOA: cofactor in the synthesis of functional forms of factors II (2), VII (7), IX (9), and X (10)
• Monitoring: NOT REQUIRED
• Indications: Hypoprothrombine mia, intestinal disorders and gastrectomy; REVERSES the effects of warfarin
• Side-effects/toxicity: hemolysis

Question 3

Oral Anti-Xa (Rivaroxaban; ~Apixaban)

• MOA?
• Monitoring?
• Indications?
• Side-effects/toxicity?

Answer 3

• MOA: inhibits factor Xa (10a)
• Monitoring: NOT REQUIRED
• Indications: stroke prevention in patients with AF; rivaroxaban also approved for prophylaxis and tx of DVT (and PE)

-Side-effects/toxicity: bleeding, liver toxicity
(-Contraindications: **PREGNANCY; severe renal or hepatic impairment; active bleeding, bleeding disorders, or conditions worsened by anticoagulation)

Question 4

Oral Antithrombin (Dabigatran)

• MOA?
• Monitoring?
• Indications?
• Side-effects/toxicity?

Answer 4

• MOA: inhibits thrombin (2a/IIa)
• Monitoring: NOT REQUIRED
• Indication: stroke prevention in patients with AF; (prophylaxis of DVT and PE)

-Side-effects/toxicity: bleeding, liver toxicity
(-Contraindications: **PREGNANCY; severe renal or hepatic impairment; active bleeding, bleeding disorders, or conditions worsened by anticoagulation)