Flashcards in Cardiovascular System Deck (61)
Which NOAC has twice daily dosing?
Which has once daily dosing?
Twice daily: Apixaban (5mg BD), Dabigatran (150mg BD)
once daily: Rivaroxiban (20mg OD)
Which NOAC requires loading?
10mg twice daily for 7 days followed by 5mg BD maintenance
Which NOAC interacts with verapamil and subsequently requires a dose reduction? What other medication has the same interaction?
Verapamil increases dabigatran levels, so patients also on verapamil need to take a reduced dose of dabigatran (110mg BD as opposed to 150mg BD)
Same with amiodarone- use max dose of 110mg dabigatran with amiodarone
Which one of the three NOACs is a DIRECT THROMBIN inhibitor?
What are the other two?
Dabigatran is a direct thrombin inhibitor
Apixaban and rivaroxaban are Direct factor Xa inhibitors (remember ban Xa)
An INR within ____ units of the target range is generally satisfactory
A target INR of ____ is used for most things! Eg treatment of DVT/PE, AF patients, electrical cardioversion, myocardial infarction...
2.5 used for most things
Apart from recurrent DVT/PE if patient was already on anticoagulation with a INR over 2 and they still got a clot... Aim for 3.5 here (thinner blood)
Or if they have a mechanical heart valve! Ask manufacturer for the target INR, also if a clot occurs whilst at the target INR then increase the target INR
Do the NOACS have any food interactions?
But remember to take Rivaroxiban with food to increase absorption
Which NOAC may be crushed an mixed with apple purée/ put through an NG tube before administration?
Which CCBs need to be avoided in Heart failure?
Verapamil and diltiazem
When should a target INR of 3.5 be used? What is the target for most other conditions?
Only when the patient has had a DVT or PE when receiving anticoagulation with warfarin / NOACs and had an INR of 2 or more, they must be susceptible to clots so need a higher target of 3.5.
For most other conditions we set a target of 2.5
Warfarin's time to peak effect ranges from 3-5 days, so it is not good if immediate effects are needed. NOACs have a much faster onset to action, what is this? Which is the fastest?
1 - 4 hours
Dabigatran fastest: peak action 0.5-2 hours after oral admin
(Apixaban and rivaroxaban take around 2-4 hours to peak)
What is the difference between Phytomenadione and Phenindinone?
Phytomenadione is the reversal agent for warfarin overdose
Phenindinone is another oral anticoagulant (coumarin) like warfarin!
What baseline tests do patients need before commencing on a NOAC?
Which NOAC is least likely to be chosen with renal impairment ?
Baseline renal function - dose reduction required in renal impairment
Dabigatran has most caution with renal function: it is CI if CrCl is under 30 ml/min
Apixaban and Rivaroxiban are less dependent on renal function
Which NOACs require hepatic metabolism therefore should not be used in severe liver disease?
We know that warfarin interacts with a lot of the CYP enzyme inhibitors and inducers, Which NOACs also have a similar problem? Can you think of any interactions?
Apixaban and Rivaroxiban
CYP3A4 inhibitors effect these: ketoconazole, itraconazole,
Inducers effect these: carbamazepine, rifampicin, phenytoin, St. John's wort
Which NOAC cannot be put in a compliance aid?
It is moisture sensitive
Shouldn't put warfarin in too
Can put Apixaban and rivaroxaban in
Which NOAC needs the warning label "swallow whole, do not chew or crush"
Opening capsules increase risk of bleeding
Which is more problematic if a dose is missed, warfarin or the NOACs?
NOACs - shorter half life so if dose is missed there is more time without coagulation
If miss a dose of a NOAC- usually take it ASAP (if within 6 hours with dabigatran) but with warfarin usually just skip it and move on to next
What is the reversal agent for LMWHs?
Name me three LMWHs
When in pregnancy should warfarin be avoided?
First trimester for sure
Crosses the placenta especially in first and third trimester
Safe in breast feeding
Which NOAC is commonly used following Total hip replacement/ knee replacement ?
Which NOAC caused the most GI side effects?
What other random SEs does this cause?
Rivaroxaban: constipation, diarrhoea, abdo pain, nausea, vomiting
pain in extremities
What is heparin induced thrombocytopenia and which heparins is it more common with?
Development of very low platelet count
It is an immune mediated reaction that can develop after 5-10 days
More common with UFH than LMWHs
Management: stop the heparin, use something else like the Heparinoid Danaparoid
What anticoagulant is indicated in patients with a history of heparin-induced thrombocytopenia?
This is a Heparinoid so won't cause the Same reaction
What heparin should we choose in patients with renal impairment?
UFH (un fractionated heparins). Still may require dose reduction
This is because the LMWHs Dalteparin, enoxaparin and tinzaparin have their risk of causing bleeds increased in renal impairment
Dalteparin vs dabigatran?
Dalteparin is LMWH
Dabigatran is a NOAC
What is the treatment for a VTE (DVT or PE)?
LMWH or UFH
Continue the heparin for at least 5 days or until the INR has been over 2 for 24 hours
LMWH usually preferred as they have a longer duration of action, however if the patient has a high risk of bleeding or has renal impairment choose UFH (as effects can be more rapidly reversed)
Warfarin usually started at same time (but takes around 3 days to start working)
Heparins are used because they give most rapid effects
What can be used for VTE treatment in pregnant women?
Heparins are Safe in pregnancy as they do not cross the placenta.
LMWHs usually preferred as they carry a lower risk of osteoporosis and heparin induced thrombocytopenia
Dose alteration will be needed as LMWHs eliminated more rapidly in pregnancy
NB: BNF states not licensed for treatment of VTE in pregnancy for Dalteparin, enoxaparin, tinzaparin