Heme Pharm Flashcards
How does heparin work?
activator of antithrombin, decreasing levels of thrombin and factor Xa (short half-life)
What are the main uses of heparin?
- immediate anticoag for PE, acute coronary syndrome, MI, DVT
- used during pregnancy
monitor PTT
What are the AEs of heparin?
bleeding
thrombocytopenia (HIT)
osteoporosis
DDIs
-monitor PTT
What is the antidote to heparin overdose?
protamine sulfate (binds to negatively charged heparin)
What are the advantages of LMWH (like enoxaparin, dalteparin) and fondaparinux?
they act more on factor Xa
better bioavailability
2-4x longer half-life
can be administered SubQ and without monitoring
What is heparin-induced thrombocytopenia?
development of IgG Abs against heparin-bound platelet factor 4, and the complex activates platelets causing thrombosis and then thrombocytopenia
What are the direct thrombin (factor II) inhibitors?
- argatroban and dabigatran
- bivalirudin
good alternatives fo anticoag in those with HIT
How does warfarin work?
it interferes with y-carboxylation of vitamin-K dependent clotting factors II, VII, IX, X, and proteins C and S
- affects PT
- long half-life
The metabolism of warfarin is affected by what?
polymorphisms in the gene for vitamin K epoxide reductase complex VKORC1)
What are the uses of warfarin?
- chronic anticoag (e.g. venous TE prophylaxis, and prevention of stroke in a. fib)
- not used in pregnancy
AEs of warfarin?
- bleeding
- teratogenic
skin/tissue necrosis
-transient hypercoagulability upon administration because of short half-life of proteins C and S
What is the antidote for warfarin OD?
vitamin K, or Fresh frozen plasma for rapid reversal
Describe heparin bridging
heparin is frequently used with starting warfarin because heparin’s activation of antithrombin enables anticoag during the initial, transient hypercoag state caused by warfarin
What is the structure of heparin?
large, anionic, acidic polymer
How is heparin given?
IV/SC
What is the onset of action and DOA of heparin?
onset of action- rapid (seconds)
DOA- acute (hours)
What is the structure of warfarin?
small, amphipathic molecule
How is warfarin given?
PO
What are the direct factor Xa inhibitors?
ApiXaban, RivaroXaban
What are the uses of direct factor Xa inhibitors?
What are the main plasmin activators?
alteplase, reteplase, tenecteplase
streptokinase
What are the AEs of plasmin activators?
-bleeding (contraindicated in pts. with active bleeding, hx of intracranial bleeding, recent surgery, or severe HTN)
How can bleeding caused by plasmin activators (or other things) be tx?
aminocaproic acid
How does aspirin work?
it irreversibly inhibits cyclooxygenase 1/2 by covalent acetylation until the platelet is degraded
How does aspirin affect BT, PT, and PTT?
BT- increased
PT/PTT- no effect
What are the AEs of aspirin?
gastric ulceration
tinnitus (the hearing of sound when no external sound is present- often ringing)
renal failure
hyperventilation and respiratory alkalosis transitioning to mixed metabolic acidosis-respiratory acidosis
What are the ADP receptor inhibitors?
clopidogrel,
prasugrel,
ticlopidine
ticagrelor (reversible)
What are the uses of ADP receptor inhibitors?
acute coronary syndrome, coronary stenting
What are the AEs of ADP receptor inhibitors?
neutropenia
TTP rarely
What do cilostazol and dipyridamole do?
phosphodiesterase III inhibitors that cause increased cAMP in platelets, resultng in inhibition of platelet aggregation
also act as vasodilators
What are the direct GpIIb/IIIa inhibitors?
-abciximab
tirofiban
-eptigibatide
What are the clinical uses of GpIIb/IIIa inhibitors?
unstable angina, percutaneous transluminal coronary angioplasty
What phase of the cell cycle do microtubules inhibitors (paclitaxel) and vinca alkaloids (vinblastine; vincristine) work?
Mitosis
What phase of the cell cycle do alkylating agents and nitrosoureas (carmustine, cisplatin, lomustine) work?
G1
What phase of the cell cycle do antimetabolites (e.g. 5-FU, methotrexate, 6-MP) work?
S