USMLE Step 1 First Aid: Heme/Onc
Pharmacology Final Exam with
Already Solved Solutions 2025-2026
Updated.
Heparin
Mechanism - Answer Inhibits *Thrombin* and *Factor Xa* (promotes antithrombin III)
Short half-life
*DOES NOT cross placenta* —> Safe for use during pregnancy
Aspirin
Mechanism - Answer Irreversible COX1/2 inhibitor --> Decreases PGI2 and TXA2
Heparin
Clinical use - Answer PE
ACS
MI
DVT
Anticoagulants of choice in *pregnancy* (does not cross placenta)
Co-administration of heparin can help "bridge" a patient past the *transient hypercoagulation
phenomena* associated w/warfarin tx initiation
Dose-dependent
Aspirin
Clinical use - Answer Pain
Fever
,Aspirin
Adverse effects - Answer Allergies
GI bleeding
Tinnitus
*Reye's syndrome*
Heparin
Adverse effects - Answer Bleeding
*Thrombocytopenia (HIT)*
Osteoporosis
Drug-drug interactions
*Monitor w/PTT or anti-Factor Xa assay*
*REMINDER* PTT measures intrinsic pathway activity
Heparin
Rapid reversal - Answer Use *protamine sulfate* (positively charged molecule that *binds*
negatively charged heparin)
Low-molecular-weight heparin (LMWH) - Answer *E*noxa*parin*, *D*alte*parin* -->
Inhibits *Thrombin* (promotes antithrombin III) and *Factor Xa*, *BUT favors Factor Xa
inhibition*; not easily reversible
Fonda*parin*u*X ONLY inhibits Factor Xa (like direct Factor Xa inhibitors); NO REVERSAL
AGENT*
Dose independent and easy to administer
*NO* monitoring required
*Better bioavailability and 2-4x longer half life than unfractionated heparin*
*B*emi*parin*, *C*erto*parin* are ultra-low-molecular-weight heparins
, Direct Thrombin Inhibitors - Answer *B*ivalirudin
*A*rgatroban
*D*abigatran
*BAD*
Direct Thrombin Inhibitor
Mechanism - Answer Directly binds and inhibits *Thrombin (Factor IIa)*
Unfractionated heparin vs. LMWH vs. Fondaparinux - Answer Unfractionated heparin
inhibits *Factor Xa and Thrombin*
LMWH (*E-, D-parin*) inhibits Factor Xa and thrombin, *BUT favors Factor Xa inhibition*
Fonda*parin*u*X* promotes inhibition of *Factor Xa only*
Direct Thrombin Inhibitor
Clinical use - Answer *Anticoagulate patients w/heparin induced thrombocytopenia* (HIT)
Venous thromboembolism
A-fib
No monitoring required
Direct Thrombin Inhibitor
Adverse effects - Answer Bleeding
*Reverse Dabigatran with Idarucizumab*
Consider *PCC (prothrombin complex concentrates) and/or antifibrinolytics (tranexamic acid)*
if *NO* reversal agent available
Warfarin
Pharmacology Final Exam with
Already Solved Solutions 2025-2026
Updated.
Heparin
Mechanism - Answer Inhibits *Thrombin* and *Factor Xa* (promotes antithrombin III)
Short half-life
*DOES NOT cross placenta* —> Safe for use during pregnancy
Aspirin
Mechanism - Answer Irreversible COX1/2 inhibitor --> Decreases PGI2 and TXA2
Heparin
Clinical use - Answer PE
ACS
MI
DVT
Anticoagulants of choice in *pregnancy* (does not cross placenta)
Co-administration of heparin can help "bridge" a patient past the *transient hypercoagulation
phenomena* associated w/warfarin tx initiation
Dose-dependent
Aspirin
Clinical use - Answer Pain
Fever
,Aspirin
Adverse effects - Answer Allergies
GI bleeding
Tinnitus
*Reye's syndrome*
Heparin
Adverse effects - Answer Bleeding
*Thrombocytopenia (HIT)*
Osteoporosis
Drug-drug interactions
*Monitor w/PTT or anti-Factor Xa assay*
*REMINDER* PTT measures intrinsic pathway activity
Heparin
Rapid reversal - Answer Use *protamine sulfate* (positively charged molecule that *binds*
negatively charged heparin)
Low-molecular-weight heparin (LMWH) - Answer *E*noxa*parin*, *D*alte*parin* -->
Inhibits *Thrombin* (promotes antithrombin III) and *Factor Xa*, *BUT favors Factor Xa
inhibition*; not easily reversible
Fonda*parin*u*X ONLY inhibits Factor Xa (like direct Factor Xa inhibitors); NO REVERSAL
AGENT*
Dose independent and easy to administer
*NO* monitoring required
*Better bioavailability and 2-4x longer half life than unfractionated heparin*
*B*emi*parin*, *C*erto*parin* are ultra-low-molecular-weight heparins
, Direct Thrombin Inhibitors - Answer *B*ivalirudin
*A*rgatroban
*D*abigatran
*BAD*
Direct Thrombin Inhibitor
Mechanism - Answer Directly binds and inhibits *Thrombin (Factor IIa)*
Unfractionated heparin vs. LMWH vs. Fondaparinux - Answer Unfractionated heparin
inhibits *Factor Xa and Thrombin*
LMWH (*E-, D-parin*) inhibits Factor Xa and thrombin, *BUT favors Factor Xa inhibition*
Fonda*parin*u*X* promotes inhibition of *Factor Xa only*
Direct Thrombin Inhibitor
Clinical use - Answer *Anticoagulate patients w/heparin induced thrombocytopenia* (HIT)
Venous thromboembolism
A-fib
No monitoring required
Direct Thrombin Inhibitor
Adverse effects - Answer Bleeding
*Reverse Dabigatran with Idarucizumab*
Consider *PCC (prothrombin complex concentrates) and/or antifibrinolytics (tranexamic acid)*
if *NO* reversal agent available
Warfarin
