Management of Patients on Blood Thinners Flashcards
what are the two types of blood thinning therapies
antiplatelet and anticoagulant
what risk is increased with these pts
higher risk for hemorrhage during oral surgical proceudres
are patients recommended to dc medications prior to minor OS procedures and why
no because this increases their risk of developing a thrombo-embolic episode
what is used for pts who do not dc meds
local measures
what do you do if pt on these meds needs major OS procedure
consult with physician and medication is withheld from pt a few days prior to surgery
who makes the decision on stopping meds
only physician
what are the commonly used antiplatelet meds
aspirin and plavix
what is aspirin
- cyclooxygenase inhibitor
- an acetylated salicylate (acetylsalicylic acid) classified amount the NSAIDs
what does aspirin do
- reduce the signs and symptoms of inflammation and exhibit a broad range of pharmacologic activities, including analgesic, antipyretic and antiplatelet properties
what is the MOA of aspirin
- irreversibly inactivates cyclooxygenase
- platelets cannot synthesize protein so cannot make thromboxane until new platelets are made
- the lack of thromboxane markedly diminishes platelet activation and aggergation
what makes aspirin different from other NSAIDs
other NSAIDs are not irreversible
- they inhibit cyclooxygenase but are effective only while drug is present
what does low dose aspirin do and what is the dosage
- 81mg/day
- irreversibly acetylates serine 530 of cyclooxygenase (COX-1) which inhibits platelet generation of thromboxane A2 resulting in antithrombotic effect
what does an intermediate dose of aspirin do and what is the dosage
- 650 mg to 4g/day
- inhibits COX-1 and COX-2, blocking prostaglandin production and have analgesic and antipyretic effects
what are the indications for low dose aspirin treatment
- low dose prophylaxis
- one children aspirin
- more doesnt work and can be harmful
- at low dose very small chance of GI bleed
- decreases incidence of MI by 2%
- cheap and safe
what is plavix used for and whats its chemical name
- clopidogrel bisulfate
- used to prevent MI and cerebro vascular accidents in people with cardiac disease, recent stroke or those with peripheral vascular disease
- works by blocking platelets from sticking together and prevents them from forming harmful clots
patients with what medical conditions take oral anticoagulants
- prosthetic heart valves
- atrial fibrillation
- valvular heart disease
- previous deep vein thrombosis
- pulmonary embolism
- congestive cardiomyopathy
what was the brand name for the generic drug warfarin sodium
coumadin
what is the new brand name for warfarin sodium
jantoven
what is the MOA of warfarin sodium
- warfarin is a vitamin K antagonist
- it affects clotting factors II, VII, IX, and X and makes them biologically inactive
- it affects factor VII first and this increases the prothrombin time
- it then affects factors IX, X and II and thereby increases the partial thromboplastin time
the coagluation status of a patient taking warfarin is assessed with:
an international normalized test (INR)
the INR is a:
standardized prothrombin time test
what was the INR developed for
to normalize the PT test based on the sensitivity of different thromboplastins
what is the formula for INR
(PT/mean normal PT) ^ISI
what is mean normal PT
the PT time based on geometric mean of 20 fresh plasmas of healthy ambulent patients
what is ISI
the international sensitivity index
what is a normal INR value
0.8-1.2
what is the name for dabigatran
pradaxa
what is dabigatran used for
to reduce stroke and systemic embolization risk in patients with non valvular atrial fibrillation
does dabigatran need to be monitored and why
at a fixed dose, no, due to predictable pharmacokinetics
which is more effective dabigatran or warfarin
equal in preventing embolic events in patients with atrial fibrillation
dabigatran is a:
direct thrombin inhibitor
what are the most sensitive tests for quantifying the anticoagulant effects of dabigatran
thrombin clotting time (TT) and ecarin clotting time (ECT)
when is dabigatran prescribed
postoperatively once a stable clot is formed so pt takes it the day after surgery
what is the name for rivaroxaban
xarelto
what is rivaroxaban and what is it used for
an orally-administerde, selective, reversible, direct inhibitor of activated factor X (factor Xa) and is currently indicated for prophylaxis of venous thromboembolism VTE in adults after hip or knee replacement surgery
what is the half life of warfarin
20-60 hours
what is the half life of dabigatran
12-17 hours and up to 28 hours in severe renal impairment
what is the half life of rivaroxaban
5-13 hours
what are the local post op hemostatic measures
- pressure guaze; 5-10 minutes until a stable clot initiates
- sutures, attempt primary closure
- absorbents
what are the absorbents
- surgicel
- gel foam
- collagen plug
- fibrin glue
