How one academic medical center has managed potency changes with unfractionated heparin

Area of Science:

• Pharmacology and Therapeutics
• Clinical Pharmacy Practice

Background:

• The United States Pharmacopeia revised standards for unfractionated heparin (UFH), reducing its potency by approximately 10%.
• No updated dosing guidelines were issued concurrently with the UFH potency change.

Purpose of the Study:

• To evaluate the clinical impact of the reduced UFH potency on achieving therapeutic activated partial thromboplastin time (aPTT).
• To assess differences in thrombotic and bleeding events between old and new UFH potencies.

Main Methods:

• A retrospective review compared patients receiving UFH before (old potency) and after (new potency) April/May 2010.
• The primary endpoint was time to therapeutic aPTT; secondary endpoints included venous thrombotic events (VTE) and bleeding events.
• Patient data included demographics, UFH dosing, aPTT values, and clinical outcomes up to 30 days post-discharge.

Main Results:

• No significant difference was observed in the time to achieve therapeutic aPTT between the old and new UFH groups (p=0.092).
• Patients receiving the new UFH potency with an initial bolus had lower aPTTs compared to those receiving the old UFH potency (p=0.003).
• There were no statistically significant differences in thrombotic or bleeding events between the two groups.

Conclusions:

• The reduction in UFH potency did not lead to clinically significant differences in therapeutic aPTT achievement or patient outcomes when dosed per institutional nomograms.
• Current dosing protocols appear adequate to manage the decreased potency of UFH, maintaining therapeutic efficacy and safety.