Mechanism of Action
This anticoagulant inhibits vitamin K epoxide reductase, decreasing factors II, VII, IX, and X.
What is warfarin?
What test is used to monitor warfarin?
What is international Normalized Ratio (INR)?
A patient on Warfarin presents with an INR of >10. What vitamin can be used to bring down a patients INR?
What Vitamin K?
This azole antifungal is a strong CYP3A4 inhibitor that can significantly increase levels of factor Xa inhibitors like Apixaban and Rivaroxaban.
*Hint: think G-PACMAN
What is Ketoconazole?
A patient weighing 154lbs is prescribed Enoxaparin for treatment of a DVT. The recommended treatment dose is 1 mg/kg every 12 hours. What would this patients dose be?
What is 70 mg?
This medication directly inhibits thrombin (factor IIa).
What is dabigatran?
For treatment of DVT/PE, this DOAC requires 15 mg twice daily for 21 days before transitioning to 20 mg daily.
What is rivaroxaban?
This medication is used to reverse heparin?
What is Protamine Sulfate?
If someone is given a CYP inducer, like St. Johns Wart, how will this effect the INR of someone on warfarin?
What is decrease INR?
Bolus: 80 units/kg
Infusion: 18 units/kg/hour
What is 6,000 units?
What factor do apixaban, rivaroxaban, edoxaban inhibit?
What is factor Xa?
A 78-year-old female with a history of hypertension, prior stroke, and heart failure presents with atrial fibrillation; what is her CHA₂DS₂-VASc score and does this require anticoagulation?
What is 7 and yes anticoagulation should be started?
0 males, 1 females: no anticoagulation
1 males, 2 females: oral anticoagulation can be considered
≥2 males, ≥3 females, oral anticoagulation
This monoclonal antibody fragment reverses the anticoagulant effects of dabigatran?
What is Idarucizumab?
This antibiotic is a strong enzyme inducer that can significantly reduce DOAC concentrations, increasing the risk of thrombosis.
*Hint: Think PS PORCS
What is rifampin?
A patient with an INR of 4.8 and no bleeding is instructed to hold 1 dose of warfarin and reduce their weekly dose by 15%; if their prior weekly dose was 40 mg, this is the new weekly dose after adjustment.
What is 34%?
What parenteral anticoagulant works by binding antithrombin and inhibiting factor Xa?
What is fondaparinux?
Age 82 years old
Weight 58 kg
Serum creatinine 1.4 mg/dL
What is 2.5 mg twice daily?
Despite no missed doses, a patient’s INR is out of range after starting a ‘green smoothie’ diet; do leafy greens cause an increase or decrease in INR?
What is decrease INR?
A patient taking Dabigatran starts an antiarrythmic medication that inhibits P-glycoprotein, potentially increasing dabigatran concentrations and bleeding risk.
Which commonly used antiarrhythmic can cause this interaction?
What is Amiodarone?
Bolus: 80 units/kg
Continuous infusion: 18 units/kg/hour
At what mL/hour rate should the infusion pump be set?
What is 14.4 mL/hr?
What are two factors that heparin inhibits to prevent the conversion of fibrinogen to fibrin?
What is factor IIa and Xa?
Also factors IXa, XIa, XIIa, plasmin
This clinical scoring tool used to evaluate the probability of Heparin-Induced Thrombocytopenia (HIT) assigns 0–2 points for four categories: Thrombocytopenia, Timing of platelet fall, Thrombosis, and other causes of thrombocytopenia.
What is the 4 T-score?
In life-threatening bleeding due to warfarin, this product is preferred over fresh frozen plasma for rapid reversal
What is 4-Factor PCC?
A patient receiving Apixaban for atrial fibrillation starts an anticonvulsant that is a strong CYP3A4 inducer. This interaction may significantly decrease anticoagulant levels and increase thrombosis risk. Which medication is responsible?
What is Carbamazepine?
A patient receiving Heparin develops thrombocytopenia with the following findings:
Platelet count decreased from 210,000 to 95,000
Platelet drop occurred 6 days after starting heparin
Patient develops a new pulmonary embolism
No other apparent causes of thrombocytopenia
Using the 4T Score, what is the total score?
What is
Thrombocytopenia >50% → 2 points
Timing day 5–10 → 2 points
Thrombosis present → 2 points
No other causes → 2 points
Total = 8 → High probability of HIT