Unfractionated heparin: Difference between revisions

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==Background==
==General==
*Binds to and activates antithrombin which in turns inactivates factor Xa and thrombin
*Type: Anticoagulant
*Anticoagulation effect lasts up to 3hr after stopping infusion
*Dosage Forms: IV, SC
*Must give IV (not subq) for acute thromboembolic disease
*Common Trade Names: Heparin
*Safe in pregnancy
 
*Unpredictable anticoagulation effect
==Adult Dosing==
**Must monitor w/ PTT; therapeutic range is 1.5-2.5x normal value
*See [https://depts.washington.edu/anticoag/home/content/heparin-infusion-guidelines University of Washington pharmacy heparin infusion guidelines]
*33% of pts develop some form of bleeding complication; 2-6% develop major bleeding
===Thromboembolism===
*Bolus: 80 units/kg IV x 1 (MAX: 5,000 units)
*Then drip: 18 units/kg/h IV (MAX: 1,000 units/h)
*Adjust dose to target aPTT levels based on nomogram
 
==Pediatric Dosing==
*IV infusion
**Initial loading dose 75 units/kg given over 10 minutes
**Initial maintenance dose 20 units/kg/hour and adjest per local policy
 
==Special Populations==
*[[Drug Ratings in Pregnancy|Pregnancy Rating]]: C
*[[Lactation risk categories|Lactation risk]]: Infant risk minimal
*Renal Dosing
**No adjustment
*Hepatic Dosing
**No adjustment
 
==Contraindications==
*Allergy to class/drug
*33% of patients develop some form of bleeding complication; 2-6% develop major bleeding
*Heparin-Induced Thrombocytopenia
*See [[HIT (Heparin-Induced Thrombocytopenia)]]


===Risk Factors for Major Bleeding Complication===
===Risk Factors for Major Bleeding Complication===
#Recent surgery or trauma
*Recent surgery or trauma
#Renal failure
*Renal failure
#Alcoholism
*Alcoholism
#Malignancy
*Malignancy
#Liver failure
*Liver failure
#Concurrent use of warfarin, fibrinolytics, steroids, or antiplatelet drugs
*Concurrent use of warfarin, fibrinolytics, steroids, or antiplatelet drugs


==Treatment ==
==Pharmacology==
#See:
*Half-life: 1.5 hrs
##[[DVT]]
*Metabolism: Hepatic
##[[PE]]
*Excretion: Urine
##[[NSTEMI]]
*Mechanism of Action:
##[[STEMI]]
**Binds to and activates antithrombin which in turns inactivates factor Xa and thrombin
 
*Anticoagulation effect lasts up to 3hr after stopping infusion
==Complications==
*Must give IV (not subq) for acute thromboembolic disease
#Bleeding
**Unpredictable anticoagulation effect
##Treatment
**Must monitor with PTT; therapeutic range is 1.5-2.5x normal value
###Managed according to clinical severity, NOT PTT value
####Heparin-associated bleeding is not always reflected by a supratherapeutic PTT
###Stop transfusion
###Observation alone may be appropriate in less severe cases
###Protamine
####Only indicated for major bleeding (0.2% of pts develop severe anaphylaxis)
####Give 1mg IV for every 100 units of UFH infused in the prior 3hr
####Give slowly over 1-3min; do not exceed 50mg in any 10 minute period
####Because half-life is short (7 min) may require second treatment
###Massive bleed
####Cryoprecipitate (10 U IV), then FFP (& platelets, aminocaproic acid infusion if nec)
#Heparin-Induced Thrombocytopenia
##See [[HIT (Heparin-Induced Thrombocytopenia)]]


==See Also==
==See Also==
*[[Low Molecular Weight Heparin]]
*[[Unfractionated heparin reversal]]
*[[Coagulopathy (main)]]
*[[Low molecular weight heparin]]


==Source ==
==References==
Tintinalli
<references/>


[[Category:Heme/Onc]]
[[Category:Pharmacology]]

Revision as of 19:08, 20 April 2019

General

  • Type: Anticoagulant
  • Dosage Forms: IV, SC
  • Common Trade Names: Heparin

Adult Dosing

Thromboembolism

  • Bolus: 80 units/kg IV x 1 (MAX: 5,000 units)
  • Then drip: 18 units/kg/h IV (MAX: 1,000 units/h)
  • Adjust dose to target aPTT levels based on nomogram

Pediatric Dosing

  • IV infusion
    • Initial loading dose 75 units/kg given over 10 minutes
    • Initial maintenance dose 20 units/kg/hour and adjest per local policy

Special Populations

Contraindications

Risk Factors for Major Bleeding Complication

  • Recent surgery or trauma
  • Renal failure
  • Alcoholism
  • Malignancy
  • Liver failure
  • Concurrent use of warfarin, fibrinolytics, steroids, or antiplatelet drugs

Pharmacology

  • Half-life: 1.5 hrs
  • Metabolism: Hepatic
  • Excretion: Urine
  • Mechanism of Action:
    • Binds to and activates antithrombin which in turns inactivates factor Xa and thrombin
  • Anticoagulation effect lasts up to 3hr after stopping infusion
  • Must give IV (not subq) for acute thromboembolic disease
    • Unpredictable anticoagulation effect
    • Must monitor with PTT; therapeutic range is 1.5-2.5x normal value

See Also

References