Anti-Xa Stability of Diluted Dalteparin for Pediatric Use

How to use low-molecular-weight heparin to treat neonatal thrombosis in clinical practice

Among children, neonates have the highest incidence of thrombosis due to risk factors such as catheter instrumentation, an evolving coagulation system and congenital heart disease. Low-molecular-weight heparins (LMWHs) are the most commonly used anticoagulants in neonates. Published guidelines delineate dosing and monitoring protocols for LMWH therapy in newborns. However, challenging clinical situations frequently present that warrant healthcare providers to think critically beyond the range of guidelines, and judiciously resolve specific problems. This review describes the use of LMWH in the neonatal population, including practical aspects such as route and site of administration, preparation from concentrated formulations and methods to minimize pain of subcutaneous injection. It is followed by a discussion on dosing, monitoring and outcomes of LMWH therapy in neonates. The risk of recurrence of thrombosis in neonates after LMWH therapy is approximately 3% based on a pooled analysis of studies reporting this outcome over the last 24 years. The article concludes with an overview of the side-effects of LMWH, including the risk of bleeding which is around 4% based on pooled analyses of more than 30 studies.

A retrospective analysis of outcomes of dalteparin use in pediatric patients: a single institution experience

BACKGROUND

Dalteparin is a commonly used low molecular weight heparin (LMWH) with extensive safety data in adults. With distinct advantages of once daily dosing and relative safety in renal impairment, it has been used off-label in pediatric practice; however, age-based dosing guidelines, safety and efficacy data in children are evolving.

OBJECTIVES

To report our institutional experience with the use of dalteparin in the treatment and prophylaxis of venous thromboembolism (VTE) in pediatric patients.

PATIENTS/METHODS

Retrospective chart review of all children (0-18years) that received dalteparin from December 1, 2000 through December 31, 2011. Doses per unit body weight per day (units/kg/day) were calculated for age-based group comparisons.

RESULTS

Of 166 patients identified, 116 (70%) received prophylactic doses while 50 (30%) received therapeutic doses of dalteparin. Infants (<1year) required significantly higher weight-based dosing to achieve therapeutic anti-Xa levels compared to children (1-10years) or adolescents (>10-18years) (mean dose units/kg/day; 396.6 versus 236.7 and 178.8 respectively, p<0.0001). Overall response rate, including complete and partial thrombus resolution, was 83%. Bleeding complications were minor and the rates were similar in therapeutic and prophylaxis patients. No significant differences in dosing or bleeding events were noted based on obesity or malignancy.

CONCLUSIONS

In our experience, dalteparin is effective for prophylaxis and therapy of VTE in pediatric patients. Dosing should be customized in an age-based manner with close monitoring of anti-Xa activity in order to achieve optimal levels, prevent bleeding complications, and to allow full benefit of prevention or therapy of thrombotic complications.

Stability and sterility of diluted enoxaparin under three different storage conditions

AIM

This study assessed whether enoxaparin sodium diluted to a concentration of 20 mg/mL for clinical use with 0.9% sodium chloride remained stable and sterile for up to 43 days under three different storage conditions.

METHODS

Enoxaparin dilutions in polypropylene syringes were stored under three different controlled conditions of temperature and light: (i) room temperature (22-26°C) under natural light; (ii) room temperature (22-26°C) in the dark; and (iii) controlled refrigeration (2-8°C) in the dark. A weekly assay of anti-Xa and anti-IIa activity was undertaken to determine if the diluted enoxaparin preparations retained anticoagulant activity, thus remaining suitable for clinical application.

RESULTS

Our findings indicate that diluted enoxaparin, when stored under the tested varied conditions of light and temperature, retained greater than or equal to 90% of baseline anticoagulant activity for anti-Xa and anti-IIa effect for up to 43 days.

CONCLUSIONS

The study results are significant for families, in that they suggest that at least a month's supply of enoxaparin could be dispensed at a time, reducing the frequency of patients/families returning for supply and providing a more convenient service for paediatric patients.