warfarin

Question 1

warfarin colours and mechanism of action

Answer 1

white= 0.5
brown= 1mg
3mg=blue
pink=5mg
antagonise vit k prevent coagulation works in 48-72hrs

Question 2

missed dose warfarin

Answer 2

<od

Question 3

dose

Answer 3

5mg initially then monitor 1-2 days
maintenance = 3-9mg same time each day

Question 4

monitoring warfarin

Answer 4

INR every 3 months once stable, for warfarin doses and change in clinical conditions
report calciphylaxis painful skin rash - sign of end stage renal disease

Question 5

duration of tx warfarin

Answer 5

isolated calf dvt= 6 weeks
provoked dvt( coc, leg cast, preg)= 3 months
unprovoked (fib)= 3 months plus / ling term

Question 6

warfarin and preg

Answer 6

teratogenic

Question 7

target inr’s (within 0.5u)

Answer 7

2.5: VTE,MI, af, cardioersion mitral vavlves
3.5: recurrent vte if on anticoag and INR >2

Question 8

S/E warfarin

Answer 8

bleeding;
inr 5.0-8.0/ no bleed= withheld 1-2 dosesreduce maintenance dose measure inr after 2/3 days

if minor bleed at this inr =omit warfarin iv phytomenadione,repeat if inr high after 24hrs, restart when warfarin <5

inr >8/ no bleed = oral phytomenadione,repest if inr still high after 24hr , restart inr <5
if minor bleed at this INR=stop warfarin, iv phytomenadione repeat after 24 restart when inr <5

if major bleed add fresh frozen plasma or dried prothrombin

Question 9

bleeding rules

Answer 9

symptoms : nose bleed10mins + , cuts that dont stop bleed , red uirne, blood in vomit , tarry stool subarachnoid haemorrhage seizure h/a

1) easy bruise avoid contact spot
2) use soft toothbrush avoid bleeding gums easy bruise

Question 10

counselling:

Answer 10

bleeding rules,pil, yellow booklet, food interaction ; alcohol binge , cranberry juice ,green leafy veg

etc interaction; miconazole, nsaid , vit e and K supplement

Question 11

counselling:

Answer 11

bleeding rules,pil, yellow booklet, food interaction ; alcohol binge , cranberry juice ,green leafy veg

etc interaction; miconazole, nsaid , vit e and K supplement

Question 12

Warfarin and surgery
elective?
VTE high risk
emergency

Answer 12

elective-stop warfarin 5 days before
vte risk; switch to LMWH
high bleed risk= LMWH 48hrs before
eMERGENCY: where warfarin wasn’t stopped give iv phytomenadione alongside

Question 13

interaction warfarin

Answer 13

increase bleed (nsaid, anticoag heparin doac antiplately ,ssri, venlafaxine tetracycline)

increase anticoag effect (enzyme inhibitors)

decrease anticoag effect (enzyme inducers)

Question 14

why nsaid and warfarin interact

Answer 14

increase bleed because nsaid has a greater affinity to albumin so more warfarin = more bleed risk

Question 15

DOAC moa

Answer 15

directly inhibit factor 10a or IIa (thrombin)

Question 16

DOAC uses and why preferred over warfarin

Answer 16

VTE,non valvular af

preferred: fixed dose regimen ,no monitoring , less food interaction

Question 17

missed dose doac, how long lasts and types

Answer 17

> 6hrs = missed
lasts 12-24hrs
doc’s = apixaban, dabigatran (special container 4m expiry), edoxaban, rivaroxaban (MHRA ; after food crush tabs)

Question 18

counselling doac, s/e and monitor

Answer 18

carry alert cards all times
1) bleeding (monitor signs bleed and anemia and rft’s in renal impairment)
if renal impair reduce dose and monitor

Question 19

c/I doac

Answer 19

1) prosthetic heart vale
2) antiphospholipid syndrome
2) taking other anticoag and significant bleed risk

Question 20

Rivaroxaban vte prevention dose (recurrent, high risk), vte tx, stroke prevention non valvular , pred atherothrombotic event

Answer 20

Vte prev: replacement 10mg od hip 35 days knee 14
Recurrent vte 10mg OD 6M+ , high risk vte= 20mg od

Vte tx 15mg bd 21 days - 20mg od
Stroke prevention - 20mg 0d
Atherothrombotic event = 2.5mg Bd (12month if after acs - only disc used after artherothrimboticcevent)

Question 21

Apixaban Eliquis dose

Answer 21

Vte prophylaxis ; replacement 2.5mg bd hip 32-38 days or knee 10-14days
Recurrent vte = 2.5mg bd

Vte tx 10mg bd 7 days , - 5mg bd

Prevention stroke in af ; 5mg bd (2.5mg bd if 80+, <61kg, creatinine 133+

Question 22

Edoxaban lixiana

Answer 22

Vte prophy, tx , stroke prevention ; 30mg 0d
61+kg = 60mg od

Question 23

Dabigatran (pradaxa)

Answer 23

VTE PREV 220MG OD HIP 35 KNEE 14
150MG OD (75+, amiodarone, verapamil)

VTE TX / STROKE PREV AF ; 150MG BD
110-150mg; (75+ mod ri, bleed risk,
110mg bd = 80+ verspamil

Question 24

Interaction doac

Answer 24

Inc bleed- antiplatelet, anticoagulant, ssri,tca, nsaid
Inc anticoagulant effect- enzyme inhibitor
Reduce effect - enzyme inducers

Question 25

Grapefruit juice and doac

Answer 25

Can have with doac not warfarin

Question 26

what to do in haemorrhage

Answer 26

avoid statin, lower htn reverse anticoagulation

Question 27

warfarin to doac switch

Answer 27

apixaban and dabigatran - stop vka start inr <2
edoxaban -stop vka start when 2.5 or less
rivaroxaban - stop vka start when inr 3 or less
(except in stroke/emobolism prev or dvt vte then 2.5 or less