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Rapid Point-of-Care Assay of Enoxaparin Anticoagulant Efficacy in Whole Blood
Published on: October 12, 2012
Optimizing therapeutic enoxaparin in preterm neonates and infants
Madeline Abbott1, Anna Bustin O'Brien1, Kelsie Ellis1
1Department of Pharmacy Services, Children's Hospital of Philadelphia, 3401 Civic Center Blvd, Philadelphia, PA 19104, USA.
Insights
Preterm neonates require a median enoxaparin dose of 2 mg/kg subcutaneously every 12 hours to reach therapeutic anti-Xa levels. This finding aids in optimizing anticoagulant therapy for this vulnerable population.
Area of Science:
- Neonatal Medicine
- Pharmacology
- Pediatric Thrombosis
Background:
- Enoxaparin is a low-molecular-weight heparin used for anticoagulation.
- Therapeutic anti-Xa levels are crucial for effective enoxaparin treatment.
- Dosing in preterm neonates and infants is not well-established.
Purpose of the Study:
- To determine the enoxaparin dose needed for preterm neonates and infants to achieve target anti-Xa levels.
- To evaluate the initial enoxaparin dose and its efficacy.
- To assess thrombotic events and bleeding in this population.
Main Methods:
- Retrospective chart review of preterm infants (<37 weeks gestation, <12 weeks postnatal age).
- Patients received subcutaneous enoxaparin every 12 hours with a target anti-Xa of 0.5-1 units/mL.
- Primary endpoint: enoxaparin dose to achieve therapeutic anti-Xa levels.
Main Results:
- Median enoxaparin dose required was 2 mg/kg subcutaneously every 12 hours.
- Initial dose of 1.7 mg/kg subcutaneously every 12 hours achieved therapeutic levels in 41% of patients.
- Thrombus progression occurred in 8%, new thrombi in 13%, and one case of pulmonary hemorrhage was reported.
Conclusions:
- Preterm neonates and infants require a median enoxaparin dose of 2 mg/kg subcutaneously every 12 hours for therapeutic anti-Xa levels.
- Current dosing guidelines may need adjustment for this population.
- Further research on optimal enoxaparin dosing in neonates is warranted.
Objectives:
The purpose of this study was to describe the enoxaparin dose required by preterm neonates and infants to achieve therapeutic anti-Xa levels.
Study Design:
Retrospective chart review of preterm infants, <12 weeks postnatal age, born before 37 weeks gestation, receiving subcutaneous (SUBQ) enoxaparin every 12 h (q12h) with an anti-Xa goal of 0.5-1 units/mL. The primary endpoint was the enoxaparin dose required to achieve a therapeutic anti-Xa level. Secondary endpoints included initial enoxaparin dose and the frequency of achieving therapeutic anti-Xa levels with the initial dose, index thrombus progression, formation of new thrombi, and suspected or confirmed bleeding.
Results:
Fifty-six patients were included for analysis. At time of enoxaparin initiation, the median gestational age, post-menstrual age, and weight were 34 weeks and 2 days, 38 weeks and 4 days, and 2.5 kg (kg), respectively. The median dose required to achieve a therapeutic anti-Xa was 2 mg/kg (IQR 1.7-2.6 mg/kg) SUBQ q12h. The median initial enoxaparin dose of 1.7 mg/kg SUBQ q12h aligned with formulary recommendations. Twenty-three patients (41 %) achieved a therapeutic anti-Xa with the initial dose. Follow-up ultrasounds were available for 38 patients, of which 3 (8 %) showed progression of the index thrombus and 5 (13 %) showed formation of a new thrombus. One patient discontinued enoxaparin due to pulmonary hemorrhage, necessitating protamine administration.
Conclusions:
Preterm neonates appear to require a median enoxaparin dose of 2 mg/kg subcutaneously every 12 h to achieve therapeutic anti-Xa levels.
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