Mx of anticoag Flashcards
Basic mechanism of anticoagulants
reduce ability of haemostatic system to respond to activation signals
3 reasons we would use anticoagulants
stroke prevention
VTE
Arterial thrombotic disease
Basic MOA of heparin
antithrombin mediated inhibition- inhibits FXa and thrombin
Basic MOA of rivaroxaban, fondaparinux and apixaban
Inhibit FXa
Basic MOA of dabigatran and argatroban
Inhibit thrombin
where do we source unfractionated heparin
derived from pig intestine or bovine lung tissue
where is lmwh derived
Derived from chemical or enzymatic degradation of UFH into fragments approximately one-third the size of heparin
is there a reversal agent for lmwh
no
can lmwh be used in pregnancy
yes
what is the reversal agent for unfractionated heparin
protamine
which is better for unplanned surgery and why- lmwh or ufh
UFH- short half life, IV nd can be started and stopped quickly
how do we monitor ufh use in the lab
APTT ratio
what can prolong APTT ratio (3)
antiphospholipid antibodies
combined Rx with warfarin or thrombolytics
congenital factor deficiencies
what 1 thing can shorten APTT ratio
high VIII
3 side effects of heparin
beeding
heparin induced thrombocytopenia
osteoporosis
MOA of warfarin
Warfarin acts as an anticoagulant by blocking the ability of Vitamin K to carboxylate the Vitamin K dependent clotting factors, thereby reducing their coagulant activity.
What must be used for alongside warfarin in the initiation of warfarin in patients with thrombosis?
heparin
4 things that can affect warfarin dose
diet (Fat and Vitamin K intake)
other drugs (+/-)
ethnicity (polymorphisms)
age
5 examples of drugs that interact with warfarin
alcohol allopurinol amiodarone antibiotics oral contraceptive pill aspirin simvastatin
lab control of warfarin is by …
INR
CIs for anticoagulation
acute bleeding active peptic ulceration alcohol or drug abuse poor compliance severe liver disease renal impairment dementia
3 side effects of warfarin
skin necrosis
coumarin embryopathy
increased fetal loss
how do we treat bleeding in pt on anticoagulation
revers anticoagulation
prothrombin complex concentration
FFP
5 advantages of newer oral anticoagulants
rapid onset/offset short half life fewer drug/food interactions limited drug-drug interactions predictable anti-coag effect
