Difference between revisions of "Unfractionated heparin"

(Adult Dosing)
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==Common Indications==
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==General==
DVT, PE, AFIB, ACS
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*Type: Anticoagulant
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*Dosage Forms: IV, SC
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*Common Trade Names: Heparin
  
==Bleeding Risk Factors==
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==Adult Dosing==
# Surgery, trauma, or stroke within the previous 14 days.
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*See [https://depts.washington.edu/anticoag/home/content/heparin-infusion-guidelines University of Washington pharmacy heparin infusion guidelines]
# History of peptic ulcer disease, GI bleeding or GU bleeding.
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===Thromboembolism===
# Platelet count less than 150K
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*Bolus: 80 units/kg IV x 1 (MAX: 5,000 units)
# Age > 70 yrs.
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*Then drip: 18 units/kg/h IV (MAX: 1,000 units/h)
# Hepatic failure, uremia, bleeding diathesis, brain metastases.
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*Adjust dose to target aPTT levels based on nomogram
  
Draw extra blue top prior to starting if concerned about a hypercoaguable state (heparin will interfere with assays)
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==Pediatric Dosing==
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*IV infusion
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**Initial loading dose 75 units/kg given over 10 minutes
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**Initial maintenance dose 20 units/kg/hour and adjest per local policy
  
==Treatment ==
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==Special Populations==
# Bolus - 150 u/kg for PE, and 80-100 u/kg for all other conditions.
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*[[Drug Ratings in Pregnancy|Pregnancy Rating]]: C
# Infuse - 15-25 u/kg/hr (high risk --> 15-18 u/kg/hr; low risk --> 22-25 u/kg/hr)
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*[[Lactation risk categories|Lactation risk]]: Infant risk minimal
# Sliding scale - PTT in 60-80 range..
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*Renal Dosing
##PTT Bolus/Hold Adjust Heparin
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**No adjustment
##<50 70 u/kg 0 Increase 200 u/hr
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*Hepatic Dosing
##50-59 0 0 Increase 100 u/hr
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**No adjustment
##60-80 0 0 No change
 
##81-99 0 0 Decrease 100u/hr
 
##>100 0 60min Decrease 200 u/hr
 
###If 1st PTT after loading dose is > 100 sec do NOT change the infusion rate unless evidence of bleeding
 
# The PTT should be checked 4-6 hrs after a new bolus or any change in the infusion dose.
 
# Other LABS to check include stool GUIAC qd and CBC (platelets) qd
 
  
Duration: DVT or PE --> 5 days of heparin (even if the INR is therapeutic earlier in hospital course)
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==Contraindications==
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*Allergy to class/drug
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*33% of patients develop some form of bleeding complication; 2-6% develop major bleeding
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*Heparin-Induced Thrombocytopenia
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*See [[HIT (Heparin-Induced Thrombocytopenia)]]
  
==Source ==
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===Risk Factors for Major Bleeding Complication===
1/22/06; DONALDSON (addapted from Lampe)
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*Recent surgery or trauma
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*Renal failure
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*Alcoholism
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*Malignancy
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*Liver failure
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*Concurrent use of warfarin, fibrinolytics, steroids, or antiplatelet drugs
  
[[Category:Heme/Onc]]
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==Pharmacology==
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*Half-life: 1.5 hrs
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*Metabolism: Hepatic
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*Excretion: Urine
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*Mechanism of Action:
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**Binds to and activates antithrombin which in turns inactivates factor Xa and thrombin
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*Anticoagulation effect lasts up to 3hr after stopping infusion
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*Must give IV (not subq) for acute thromboembolic disease
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**Unpredictable anticoagulation effect
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**Must monitor with PTT; therapeutic range is 1.5-2.5x normal value
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==See Also==
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*[[Unfractionated heparin reversal]]
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*[[Coagulopathy (main)]]
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*[[Low molecular weight heparin]]
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==References==
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<references/>
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[[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