Neonatal Drug Therapy Manual


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Alternate Name(s): 
Antithrombotic-low molecular weight heparin
Original Date: 
August 2003
Revised Date: 
April 2017
  • Prophylaxis and treatment of thromboembolic disorders
  • SC

< 2 months:

  • Treatment dose: 3.5 mg/kg/day divided Q12H
  • Prophylactic dose: 1.5 mg/kg/day daily or divided Q12H

> 2 months and PNA > 38 weeks:

  • Treatment dose: 2 mg/kg/day divided Q12H
  • Prophylactic dose: 1 mg/kg/day daily or divided Q12H
Side Effects: 
  • CNS: fever
  • CVS: edema, hypotension
  • Hematologic: bruising, hematemesis, nosebleed, melena, coffee ground emesis, hematuria, hemoptysis, thrombocytopenia (incidence or heparin-induced thrombocytopenia is less than with heparin therapy)
  • Local: irritation, pain, hematoma, local erythema
Parameters to Monitor: 
  • CBC, PT, and APTT prior to initiation of enoxaparin
  • Platelets, antifactor Xa level (if initial measurement is therapeutic, monitor once weekly)
  • Serum creatinine (elimination may be delayed in renal impairment-monitor antifactor Xa levels closely)
  • Therapeutic antifactor Xa level (measure 4 - 6 hours after SC administration)
    • Treatment dose: 0.5 - 1 unit/mL
    • Prophylactic dose: 0.2 - 0.4 units/mL
Reconstitution and Stability: 


  •  20 mg/mL Enoxaparin syringe prepared by pharmacy (doses < 10 mg)
  • 100 mg/mL Enoxaparin syringe prepared by pharmacy (doses > 10 mg)


  • Enoxaparin 30 mg/0.3 mL - prefilled syringe
    • Take 0.3 mL (30 mg) add to 1.2 mL of 0.9% NaCl
    • Final concentration: 20 mg/mL


  • Antidote:
    • Discontinue enoxaparin
    • 1 mg of protamine per 100 units (1 mg) of enoxaparin given in last dose (administer protamine IV over 10 minutes)
  • Hold enoxaparin for 2 doses prior to invasive procedures (eg. Spinal puncture)

- Monagle P, Chan AK, Goldenberg NA, Ichord RN, Journeycake JM, Nowak-Gottl U, Vesely SK.  Antithrombotic therapy in neonates and children: antithrombotic therapy and prevention of thrombosis, 9th ed: American College of Chest Physicians evidence-based clinical practice guidelines. Chest: 2012 Feb; 141 (2 Suppl): e737S-801S.

- Malowany, J.I., Knoppert, D.C., Chan, A.K.C., Pepelassis, D., and Lee, D.S.C. (2007). Enoxaparin Use in the Neonatal Intensive Care Unit: Experience Over 8 Years.  Pharmacotherapy, 27: 1263-1271.

-Taketomo CK, Hodding JH, Kraus DM. Pediatric Dosage Handbook 22nd Editions. Hudson: Lexi-Comp Inc.; 2015

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