question... - usmle19

[ArchivalUser]

hi...
why in post op period warf & heparin strated toghter???

[ArchivalUser]

this is called bridging since u have to continue with heparin till warfarin starts working

[ArchivalUser]

In short heparin stimulates the activity of antitrombin 111 which is a potent inhibitor of throorbin
(factor 2) as well as several other factors in the intrinsic pathway. because of this preferencial inhibition heparin acts rapidly to prolong the aPTT., but will prolong PT at higher doses.
Wafarin on the other hand inhibits the production of vit. k-dependent clotting factors in the liver
(27910), it preferentially prolongs PT.
NOW because inhibits the synthesis of the clotting factors rather than their activity in the blood
there is delay between administration and onset of action (typically a few days)>
For this reason patients who require long term anticoagulation are usuallicy started on heparin and
wafarin silmutaenously, and once the patient is sufficiently well anticuagulated with wafarin,the
heparin can be discontinued and the PT maintained within a therapeutic range.

[ArchivalUser]

ya ...more of that....warf also inhibit natural anticoalugant of body...protein c, pro s within few hrs (i think 4-6 hrs)...thus it promotes the coagulation........but its anticoagulaant axn start after few days so to counteract this coagulant axn ...we need to start heparin which is rapidly acting ...!!!& we bridge them.....!!1

[ArchivalUser]

hypercoaguable state due to protein S inhibition mainly.......6 hrs half life.....more prevalent in patients with protein C deficiency.....as practically does not need warfarin induced inhibition of protein C already levels low........also assoc with protein S def......can lead to warfarin induced skin necrosis esp in areas with more sc fat........as lots of microvasculature thrombi develop there.........abdomen, hips, breasts......

how wud u rx it?

[ArchivalUser]

hmm..

for warf induced skin necrosis....two ways to deal...

1. stop warf...start LMWH,give FFP & vit K....try to revese the drug effect...

2. local wound care....dressing & local antibiotics...!! RIGHT!!!

[ArchivalUser]

yup.....local debridement also as necrosed tissue