Heparin/Warfarin Flashcards
Warfarin
- mechanism of action
- placental transfer
- teratogenic
- acceptable in pregnancy?
- lab for monitoring?
- clinical aim
- dose
- antidote
- side effect
- half-life
- mechanism of action: factors 2, 7, 9, 10
- placental transfer: yes
- teratogenic: yes
- acceptable in pregnancy?: no
- lab for monitoring?: PT
- clinical aim: 2.0-3.0 x control
- dose: variable
- antidote: vitamin K
- side effect: fetal bleeding, fetal coumadin syndrome (1st trimester: stippled epiphyses, limb + nasal hypoplasia; 2nd trimester: optic atrophy + microcephaly)
- half-life: 4 hours
Heparin
- mechanism of action
- placental transfer
- teratogenic
- acceptable in pregnancy?
- lab for monitoring?
- clinical aim
- dose
- antidote
- side effect
- half life
- mechanism of action: co-factor for antithrombin, increases inhibition of thrombin & factor Xa
- placental transfer: no
- teratogenic: no
- acceptable in pregnancy?: yes
- lab for monitoring? : PTT
- clinical aim: 1.5-2.0 x control
- dose: 1000 u or 6000 u q6hours, ppx = 5000 u BID
- antidote: protamine sulfate
- side effect: maternal thrombocytopenia, osteoporosis (both with long term use)
- half life: 1.5 hours
LMWH (enoxaparin)
- mechanism of action
- placental transfer
- teratogenic
- acceptable in pregnancy?
- lab for monitoring?
- clinical aim
- dose
- antidote
- side effect
- half life
- mechanism of action: inhibits factor Xa (better than regular heparin)
- placental transfer: no
- teratogenic: no
- acceptable in pregnancy?: yes
- lab for monitoring?: anti-xa every 4-6 weeks
- side effect: thrombocytopeni, osteoporosis, post-op bleeding
- half life - longer half life than heparin
Increased risk of epidural hematoma:
wait > 12 hours prior to epidural with ppx dosing
wait > 24 hrs with ttx dosing
Contraindicated with prosthetic valves unless v close dosing
normal clotting changes in pregnancy
increased in thrombotic activity: 5, 7, 9, 10, 12, and fibrinogen
decrease in fibrinolytic activity: mild to endogenous protein c and s; increased plasminogen activator inhibitor type I and II
what mutations warrant ppx anticoagulation (or intermediate anticoagulation) without a hx of VTE? (i.e. what are high risk thrombophilias)
high risk (i.e. risk of VTE 3% or higher)
- factor v leiden mutations homozygous
- prothrombin G20210A gene mutation, homozygous
- antithrombin III deficiency
- double heterozygous prothrombin G20210A gene mutation and FVL mutation
- APAS
- personal hx of VTE (outside of trauma)
who should be screened for inherited thrombophilia?
- pts with prior VTE and no work-up
- first degree related with inherited thrombophilia
what should be tested for in people who are being eval’d for inherited thrombophilias? which is not reliable in pregnancy?
- FVL
- prothrombin gene mutation G20210A
- Protein C deficiency
- Protein S Deficiency
- Antithrombin deficiency
- APAS
Protein S not reliable in pregnancy
high risk thrombophilia with prior VTE or affected family member?
- ppx, intermediate, or adjusted dosing
high risk thrombophilia with 2 or more prior VTE
- intermediate or adjusted dosing
thrombophilia with 2 or more prior VTE? on long term anticoagulation vs not?
not on long term anticoagulation: intermediate or adjusted dosing
on long term: adjusted dosing
when to start anticoagulation after delivery?
no clear data, consider:
4-6 hrs after VD
6-12 hrs after CD
if ppx heparin, 4-6 hrs after last dose
what is ppx dosing for heparin, lovenox?
intermediate dosing?
adjusted dosing?
ppx: heparin depends by trimester (1st: 5K-7.5K q12hr, 2nd: 7.5-10K q12hr, 3rd: 10K q12hr can check with PTT), lovenox 40 mg qday
intermediate: lovenox 40 mg q12hr
adjusted dosing: heparin 10K q12 hr (or uptitrate until PTT is 1.5-2.5x/control), lovenox 1 mg/kg q12hr
okay to breastfeed? warfarin, heparin, LMWH?
yes- all
what concern may you have starting warfarin in postpartum period?
paradoxical thrombosis/skin necrosis due to anti-protein C activity– need bridging until INR 2-3 for 2 consecutive days
what is the highest thrombogenic risk with high risk thrombophilias?
30-50% - antithrombin III deficiency
the rest ~ 5%
