Warfarin Flashcards
What are the main side effects of warfarin?
haemorrhage
teratogenic, although can be used in breastfeeding mothers
skin necrosis
purple toes
In who can warfarin be used although it is teratogenic?
Breastfeeding mothers
How are patients on warfarin monitored?
INR
What is the INR?
The ratio of the prothrombin time for the patient over the normal prothrombin time.
What does INR stand for?
International normalised ratio
What are the man inidcations of use for warfarin?
Mechanical heart valves
Second line after DOAC’s for AF and VTE
When is warfarin used second line?
After DOAC’s for AF and VTE
What is the target INR for second line in VTE and AF?
2.5
What is the management of someone on warfarin having a major bleed?
Stop warfarin
Give intravenous vitamin K 5mg
Prothrombin complex concentrate - if not available then FFP*
What is the management of someone on warfarin with an INR > 8.0 and minor bleeding?
Stop warfarin
Give intravenous vitamin K 1-3mg
Repeat dose of vitamin K if INR still too high after 24 hours
Restart warfarin when INR < 5.0
What is the management of someone on warfarin with INR > 8.0 and
No bleeding?
Stop warfarin
Give vitamin K 1-5mg by mouth, using the intravenous preparation orally
Repeat dose of vitamin K if INR still too high after 24 hours
Restart when INR < 5.0
What is the management of someone in warfarin with INR 5.0-8.0 and minor bleeding?
Minor bleeding Stop warfarin
Give intravenous vitamin K 1-3mg
Restart when INR < 5.0
What is the management of INR 5.0-8.0 and no bleeding?
Withhold 1 or 2 doses of warfarin
Reduce subsequent maintenance dose
What are the possible interactions that could occur with Warfarin?
liver disease
P450 enzyme inhibitors (see below)
cranberry juice
drugs which displace warfarin from plasma albumin, e.g. NSAIDs
inhibit platelet function: NSAIDs
