Enoxaparin for neonatal thrombosis: A call for a higher dose for neonates

INTRODUCTION: Enoxaparin is the current anticoagulant of choice for neonatal thrombosis. Present neonatal treatment guidelines of 1.5 mg/kg every 12 hours (q12 h) are extrapolated primarily from an earlier study with 9 infants less than 2 months of age. More recent studies indicate an increased dose requirement for neonates. MATERIALS AND METHODS: Relevant data from articles and abstracts were identified by searching MEDLINE and pediatric and hematology conference proceedings. RESULTS: Publications between 1996 and 2007 included 8 papers, 4 abstracts and 1 review article with primary research documenting enoxaparin use in 240 neonates. The mean maintenance dose of enoxaparin ranged from 1.48 to 2.27 mg/kg q12 h for all infants, but was higher for preterm neonates at 1.9-2.27 mg/kg q12 h. The efficacy of enoxaparin, causing either complete or partial resolution was between 59 and 100%. Minor side effects were common and adverse events (major bleeding) occurred in 12 patients (0-19%). CONCLUSIONS: Increased experience with enoxaparin use in neonates in the past decade has indicated higher doses to achieve accepted target anti-factor Xa values. The long-term use of indwelling catheters (Insuflon catheter) for enoxaparin administration may need to be reevaluated in ELBW infants. Suggested starting doses of enoxaparin are 1.7 mg/kg q12 h for term neonates and 2.0 mg/kg q12 h for preterm neonates if there is no considerable bleeding risk. However, further prospective studies are needed to validate an increased initial dose of enoxaparin.