Enoxaparin is a low molecular weight heparin (LMWH) commonly used for thromboprophylaxis children. Enoxaparin dosing is based on patients' weight and results in decimal dosing. Due to the high concentration of enoxaparin the resultant decimal dose makes precise measurement difficult. Dilution is necessary and often results in ten-fold medication administration errors [Ghaleb MA, Barber N, Franklin BD, Yeung VWS, Khaki ZF, Wong ICK. Systematic review of medication errors in pediatric patients. Ann Pharmacother Oct 2006;40(10):1766-76, Raju TN, Kecskes S, Thornton JP, Perry M, Feldman S. Medication errors in neonatal and paediatric intensive-care units. Lancet Aug 12 1989;2(8659):374-6]. Enoxaparin may be administered in whole milligram doses via insulin syringe, where one milligram of enoxaparin equals one unit on the 100 unit graduated insulin syringe.
Study design: A retrospective chart review of 514 children. Data was collected on underlying diagnosis, reason for anticoagulation, anti-Xa levels, hemorrhagic events, and medication errors identified.
Outcome: to determine the occurrence rate of supra-therapeutic anticoagulation as indicated by anti-Xa levels >1.0 u/ml, when enoxaparin doses are rounded up to the whole milligram, and are administered using insulin syringes. The secondary objectives were to determine if the supra-therapeutic anti-Xa levels were associated with hemorrhagic events. To determine if children achieved and maintained therapeutic anti-Xa range using whole milligram dosing and to evaluate the impact of utilizing insulin syringes for administration on reducing dose measurement errors.
Results: All 514 patients were prescribed whole milligram enoxaparin dosing, and achieved therapeutic anti-Xa within a mean time of 2 days. No infant or child required decimal doses to achieve therapeutic levels. Five children achieved an initial supra-therapeutic anti-Xa level (1.04 -1.36 U/ml), requiring a single whole milligram dose decrease. There were no associated hemorrhagic events.
Conclusion: Whole milligram enoxaparin dosing administered via an insulin syringe safely and effectively, achieved therapeutic levels in infants and children. The reduced incidence of enoxaparin dosing errors suggests that whole milligram enoxaparin dosing via an insulin syringe is a method that should be considered for standard of care.