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Published on: October 12, 2012
Evaluation of Initial Enoxaparin Dosing and Antifactor Xa Levels in Infants Admitted to the Neonatal Intensive Care
Rosemarie Nagy1, Trina Hemmelgarn2, Stephen Deptola2
1Department of Pharmacy, Nemours Children's Hospital, Orlando, FL, USA.
Insights
Infants in the neonatal intensive care unit (NICU) often need higher initial enoxaparin doses than recommended to achieve therapeutic levels. This study found higher enoxaparin dosing is required for infants to reach target antifactor Xa levels.
Area of Science:
- Pediatric Thrombosis and Anticoagulation
- Neonatal Intensive Care Unit (NICU) Pharmacotherapy
Background:
- Infants face thrombotic risks from conditions like congenital heart defects and sepsis.
- Current American College of Chest Physicians (ACCP) 2012 guidelines suggest enoxaparin dosing for infants based on age, but studies indicate higher doses may be needed.
- Reaching therapeutic antifactor Xa levels is crucial for effective anticoagulation in infants.
Purpose of the Study:
- To compare the initial enoxaparin dose with the dose required to achieve a therapeutic antifactor Xa level (0.5-1.0 units/mL) in hospitalized infants.
- To evaluate if current enoxaparin dosing recommendations are adequate for infants in the NICU.
Main Methods:
- A single-center retrospective case-control study.
- Inclusion criteria: hospitalized infants (<12 months) treated with enoxaparin in the NICU.
- Objective: Analyze the difference between initial enoxaparin dose and the dose at which therapeutic antifactor Xa levels were first achieved.
Main Results:
- Fifty-six infants were included in the study.
- The median initial enoxaparin dose was 1.5 mg/kg/dose, while the median dose to reach a therapeutic antifactor Xa level was 1.9 mg/kg/dose (p < 0.0001).
- No correlation was found between gestational age or weight and the enoxaparin dose needed for therapeutic levels.
Conclusions:
- Infants, particularly those under 4 months old admitted to the NICU, require higher initial enoxaparin doses than currently recommended to achieve therapeutic antifactor Xa levels.
- Current dosing guidelines may be insufficient for optimizing enoxaparin therapy in this vulnerable population.
Introduction:
Infants are at risk for thrombotic conditions due to multiple risk factors such as congenital heart defects and sepsis. According to the American College of Chest Physicians (ACCP) 2012 guidelines, enoxaparin may be given for thrombotic conditions at a dose of 1.5 mg/kg/dose every 12 h for patients less than 2 months of age and 1 mg/kg/dose every 12 h for those older than 2 months. Several studies have reported that infants typically require a higher initial dose of enoxaparin to reach therapeutic antifactor Xa levels than what is currently recommended.
Methods:
This is a single-center retrospective case-control study of hospitalized infants less than 12 months of age who received treatment with enoxaparin while admitted to the neonatal intensive care unit (NICU) at a freestanding children's hospital. The primary objective was the difference between the initial enoxaparin dose (mg/kg) compared to the enoxaparin dose in which the patient first achieved a therapeutic antifactor Xa level of 0.5-1.0 units/mL.
Results:
A total of 56 infants were included in this study. The median enoxaparin dose at initiation was 1.5 mg/kg/dose, and the median enoxaparin dose at the first therapeutic antifactor Xa level was 1.9 mg/kg/dose (z = -12.7, p < 0.0001). There was no correlation between gestational age and weight with the enoxaparin dose required to reach a therapeutic antifactor Xa level.
Conclusion:
Infants admitted to the NICU, specifically those less than 4 months of age, require higher initial enoxaparin dosing to reach therapeutic antifactor Xa levels than what is currently recommended.
