Unfractionated heparin

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

• Pregnancy Rating: C
• 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
• 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.

	Indication	Dose	Context	Route	Population
Acute arterial ischemia#Unfractionated heparin Anticoagulation to prevent clot propagation Adult	Acute arterial ischemia	80 units/kg bolus, then 18 units/kg/hr infusion	Anticoagulation to prevent clot propagation	IV	Adult
Non-ST-elevation myocardial infarction#Unfractionated heparin Antithrombotic; consider if PCI/CABG within 24hr or renal failure Adult	Non-ST-elevation myocardial infarction	60-70 units/kg bolus (max 5000), then 12-15 units/kg/hr (max 1000/hr)	Antithrombotic; consider if PCI/CABG within 24hr or renal failure	IV	Adult
Pulmonary embolism#Unfractionated heparin Anticoagulation (preferred if rapid reversal needed) Adult	Pulmonary embolism	80 units/kg IV bolus, then 18 units/kg/hr continuous infusion	Anticoagulation (preferred if rapid reversal needed)	IV drip	Adult
ST-segment elevation myocardial infarction#Unfractionated heparin Anticoagulation (required with thrombolytics/PCI) Adult	ST-segment elevation myocardial infarction	60 units/kg IV bolus (max 4000 U), then 12 units/kg/hr (max 1000 U/hr); titrate to PTT 1.5-2.5x control	Anticoagulation (required with thrombolytics/PCI)	IV drip	Adult
Unstable angina#Unfractionated heparin Antithrombotic Adult	Unstable angina	60 units/kg IV bolus (max 4000 units), then 12 units/kg/hr (max 1000 units/hr)	Antithrombotic	IV	Adult

See Also

• Unfractionated heparin reversal
• Coagulopathy (main)
• Low molecular weight heparin