Heparin

An IV heparin protocol

When intravenous UFH is initiated for DVT anticoagulation, the goal is to achieve and maintain an elevated activated partial thromboplastin time (aPTT) of at least 1.5 times control. Heparin pharmacokinetics are complex, and the half-life is 60-90 minutes. A protocol for IV heparin use is as follows:

• Give an initial bolus of 80 U/kg.
• Initiate a constant maintenance infusion of 18 U/kg.
• Check the aPTT or heparin activity level 6 hours after the bolus, and adjust the infusion rate accordingly.
• Continue to check the aPTT or heparin activity level every 6 hours, until 2 successive values are therapeutic.
• Monitor the aPTT or heparin activity level, hematocrit, and platelet count every 24 hours.