Week 6 - Anticoagulants & Dentistry Flashcards
which medical conditions can predispose individuals to risk of thrombosis (with potential for heart attack, pulmonary embolism or stroke)
- atherosclerosis
- cardiac arrhythmias
anticoagulants - prescribed to reduce the risk of thrombosis in patients with what conditions?
- vascular/thromboembolic conditions
- cardiac arrhythmias
- history of stroke
- following heart valve replacement surgery
- cardiac stents
- joint replacement
anticoagulants - dental aspects?
reduced risk of thromboembolic events comes at the cost of an increased risk in what?
what should be the consideration for these patients in their management?
- comes with an increased tisk of bleeding spontaneously or bleeding associated with invasive procedures
- balance risks and benefits for the patient that requires dental treatment
anticoagulant treatment: most commonly used anticoagulants are?
- warfarin
- antiplatelet drugs
- novel oral anticoagulants (NOAC)
warfarin - what is it an antagonist to?
vitamin k
warfarin: how does it inhibit coagulation? takes how long for anticoagulant effect to develop? action reversible by?
- it inhibits coagulation by antagonizing vitamin K
- takes at least 48-72 hours
- reversible by vitamin k
what are the limitations of warfarin?
- narrow therapeutic range
- sensitivity to diet
- drug interactions
- requires frequent monitoring and dose adjustment
warfarin - monitoring:
overall effect of oral anticoagulants can be measured by?
what is the normal range for prothrombin time?
- can be measured by the International Normalized Ratio (INR) test which is the prothrombin time ratio
- INR approx. 1
INR above 1 indicates what?
that clotting will take longer than normal
general management of warfarin: what is the information required prior to examination?
- INR needs to be accessed 72 hours before procedure
- INR stable: see BNF definition
- INR should be below 4
what is the definition of a stable INR?
- patient does not require weekly monitoring
- INR has not been above 4 the past two months
warfarin: management
when is the ideal time to check patient’s INR before treatment?
- ideally 24 hours before procedure, but if INR stable can be up to 72 hours
warfarin: management?
what to do if patient’s INR above 4?
- inform patient’s GMP or anticoagulation service
- delay treatment
- if urgent -> refer to secondary dental care
warfarin: management during treatment
- how should treatment be modified? x3
- limit initial treatment area
e. g. carry out single extraction first, limit scaling and RSD to limited area to access potential for bleeding - suturing over socket with an absorbable haemostatic dressing is essential
local anaesthetic - is considered it risky? why?
- no
- because it is unlikely to cause bleeding
advice should be sought from GMP or anticoagulant clinic if?
- unstable INR
- INR >4 in last 2 months
- other disorders of haemostasis
- renal failure, liver disease or alcoholism
- patient receiving cytotix drugs or radiotherapy
interactions with warfarin: drugs that increase warfarin activity?
- antibacterials
- antiepileptics
- antifungals
- hormones
- cardiac drugs
- analgesics
interactions with warfarin: drugs that decrease warfarin activity?
- antiepileptics
- antifungals: nystatin
- cardiac drugs
- analgesics
- others e.g. oral contraceptives
warfarin: effects can also be influenced by what?
- irregular tablet taking
- diets high in vitamin k
- alcohol ingestion
- cranberry juice (enhances effects)
antiplatelet drugs: name 2 examples?
- aspirin
- clopidogrel
antiplatelet drugs: aspirin prescribed for?
- prophylaxis of cerebrovascular disease
- MI
- can also be self-prescribed
antiplatelet drugs: clopidogrel used for?
- used in conjunction with low dose long term aspirin
novel oral anticoagulants:
name examples?
example of when to use?
requires anticoagulant monitoring?
- rivaroxaban, apixaban, dabigatran
- prophylaxis of venous thromboembolism in adults after hip/knee replacement surgery
- does not require anticoagulant monitoring
general advice for patients taking anticoagulants or antiplatelet drugs?
- plan treatment for early in the day and week
- use appropriate local measures
- only discharge patient when haemostasis achieved
- place particular emphasis on measures to avoid complications (esp when travel time is far)
- provide post treatment advice and emergency contact details
