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]]
*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
 
===Acute Coronary Syndrome===
*Bolus: 50 units/kg IV x 1 (MAX: 5,000 units)
*Then drip: 12 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
*[[HIT (Heparin-Induced Thrombocytopenia)]]
 
===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
 
==Adverse Reactions==
===Serious===
*Major bleeding
*Thrombocytopenia
 
===Common===
*Injection site reaction<ref>Warnock LB, Huang D. Heparin. [Updated 2022 Jul 12]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK538247/</ref>
*Hyperkalemia
*Alopecia
*Osteoporosis
 
==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
*Anticoagulation effect lasts up to 3hr after stopping infusion
*Must give IV (not subq) for acute thromboembolic disease
*Must give IV (not subq) for acute thromboembolic disease
*Safe in pregnancy
**Unpredictable anticoagulation effect
*Unpredictable anticoagulation effect
**Must monitor with PTT; therapeutic range is 1.5-2.5x normal value
**Must monitor w/ PTT; therapeutic range is 1.5-2.5x normal value
*33% of pts develop some form of bleeding complication; 2-6% develop major bleeding


===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


==Treatment ==
==Indications by Condition==
#See:
''The following table is automatically generated from disease/condition pages across WikEM.''
##[[DVT]]
##[[PE]]
##[[NSTEMI]]
##[[STEMI]]


==Complications==
{{#ask:[[Has DrugName::Unfractionated heparin]]
#Bleeding
|?Has Indication=Indication
##Treatment
|?Has Dose=Dose
###Managed according to clinical severity, NOT PTT value
|?Has Context=Context
####Heparin-associated bleeding is not always reflected by a supratherapeutic PTT
|?Has Route=Route
###Stop transfusion
|?Has Population=Population
###Observation alone may be appropriate in less severe cases
|format=table
###Protamine
|headers=plain
####Only indicated for major bleeding (0.2% of pts develop severe anaphylaxis)
|mainlabel=-
####Give 1mg IV for every 100 units of UFH infused in the prior 3hr
|sort=Has Indication
####Give slowly over 1-3min; do not exceed 50mg in any 10 minute period
|limit=50
####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]]

Latest revision as of 21:55, 20 March 2026

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

Acute Coronary Syndrome

  • Bolus: 50 units/kg IV x 1 (MAX: 5,000 units)
  • Then drip: 12 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

Adverse Reactions

Serious

  • Major bleeding
  • Thrombocytopenia

Common

  • Injection site reaction[1]
  • Hyperkalemia
  • Alopecia
  • Osteoporosis

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


Indications by Condition

The following table is automatically generated from disease/condition pages across WikEM.

IndicationDoseContextRoutePopulation
Acute arterial ischemia80 units/kg bolus, then 18 units/kg/hr infusionAnticoagulation to prevent clot propagationIVAdult
Non-ST-elevation myocardial infarction60-70 units/kg bolus (max 5000), then 12-15 units/kg/hr (max 1000/hr)Antithrombotic; consider if PCI/CABG within 24hr or renal failureIVAdult
Pulmonary embolism80 units/kg IV bolus, then 18 units/kg/hr continuous infusionAnticoagulation (preferred if rapid reversal needed)IV dripAdult
ST-segment elevation myocardial infarction60 units/kg IV bolus (max 4000 U), then 12 units/kg/hr (max 1000 U/hr); titrate to PTT 1.5-2.5x controlAnticoagulation (required with thrombolytics/PCI)IV dripAdult
Unstable angina60 units/kg IV bolus (max 4000 units), then 12 units/kg/hr (max 1000 units/hr)AntithromboticIVAdult

See Also

References

  1. ↑ Warnock LB, Huang D. Heparin. [Updated 2022 Jul 12]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK538247/
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