Hematology/Oncology Flashcards
What is the MOA for heparin?
Potentiate the effects of Antithrombin to primarily inhibit clotting factors 2a and 10a
What lab values should be followed when a patient is on heparin? (2)
What is considered therapeutic levels?
PTT (60-90 seconds is therapeutic)
Antifactor Xa levels
What is the half life of standard heparin and when will it cease to have an effect on a patient?
Standard heparin half life is 1 hour. Cease to have an effect on a patient in 4 hours.
What is the half-life for LMWH?
3-24 hours
What are the indications for heparin use?
- Venous Thrombosis: DVT, PE
- Acute Coronary Syndromes: Unstable angina, MI
- Afib in acute setting
- After vascular bypass grafting
What is the dosing for standard heparin?
Bolus initiated with 70-80 U/kg and followed by continuous infusion 15-18 U/kg/hr infusion)
When is heparin dosing not needed?
When the heparin is given subcutaneously.
What are the adverse effects of heparin?
Bleeding
Heparin induced thrombocytopenia
Possible osteoporosis
Rebound hypercoagulability after removal due to depression of antithrombin 3
What blood disorders are contraindications to heparin? (2)
Hemophilia and thrombocytopenia
How is heparin reversed? (2)
Protamine sulfate
If the patient has severe bleeding, give FFP
How does the MOA of LMWH differ from Heparin?
LMWH mostly inhibits 10a but not 2a as much as heparin
What are some names of LMWH?
Enoxaparin
Dalteparin
Tinzaparin
-PARIN
What labs need to be monitored with LMWH?
None, given subcutaneously
What is a contraindication for use of LMWH?
Severe kidney disease
What is the MOA of Warfarin? What factors does it affect?
Vitamin K antagonist. Leads to a decrease of clotting factors C, S, 2, 7, 9, 10
What lab values should be monitored on patients on warfarin?
PT (causes prolongation)
INR (causes an increase)
How long does warfarin take to take effect?
4-5 days.
How should warfarin should be bridged?
Start heparin. Once PTT becomes therapeutic, start warfarin. Check INR after 4 days to make sure it is between 2-3.
What is considered a therapeutic PTT for patients on heparin?
60-90 seconds
What is the INR goal for patients on warfarin and mechanical valves?
INR of 2.5-3.5
What are the adverse effects of warfarin? (3)
- Hemorrhage. Do not use in patient susceptible to falls (alcoholics)
- Rare skin necrosis if protein C (which depends on vitamin K) drops
- Teratogen
What is the mechanism of action for clopidogrel?
Blocks ADP to a specific platelet ADP receptor P2Y12 which reduces platelet activation and aggregation
What lab value does clopidogrel affect?
Bleeding time increases
What are the indications for anti-platelets like clopidogrel? (3)
Acute Coronary Syndrome like unstable angina, stable angina, STEMI, NSTEMI
Pretreatment for patients undergoing PCI
Treatment for patients for 1 year post-stents
