Chapter 15 Antithrombolytic therapy
All patients &/or families should receive teaching prior to discharge on this medication. Pediatric neurosurgery patients need clearance prior to initiating enoxaparin.
15.1 Dosing
Create Enoxaparin Order Set for avoiding errors in dosing.
- Doses ≤ 10 mg – Round to nearest 0.1 mg
- Doses 11- < 40mg – Round to nearest 1 mg
- Doses ≥ 40 mg – Round dose to nearest 5 mg
- Time dose to be administered between the hours of 8:00 and 22:00 if possible, to avoid waking patient in the middle of the night for injections
15.2 LMW Heparin Assay (Anti-Xa) Monitoring for Treatment Dosing
Due to variability in dose response, routine monitoring of the LMW Heparin concentration (Anti-Xa) in children and neonates receiving treatment dose enoxaparin is necessary. * Draw first LMW Heparin assay in the morning, 4 hours after the 2 or 3 dose * If therapy is interrupted (≥ 2 doses held) and restarted, obtain a new LMW heparin assay after the 2 or 3 dose
- Target LMW Heparin concentration (Anti-Xa) for treatment is 0.5 – 1 units/mL
- Target LMW Heparin concentration (Anti-Xa) for prophylaxis is 0.2 - 0.4 units/mL
15.3 Dose adjustement for Treatment dose
| Anti-Xa Value (units/mL) | Hold Next Dose | Dose Change | Repeated Anti-Xa Value |
|---|---|---|---|
| <0.35 | No | Increase 25% | 4 hr after second dose given |
| 0.35–0.49 | No | Increase 10% | 4 hr after second dose given |
| 0.51 | No | No change | Repeat once within 24–48 hr, then once weekly |
| 1.01–1.5 | No | Decrease 20% | 4 hr after second dose given |
| 1.51–2 | 3 hr | Decrease 30% | 4 hr after second dose given |
| >2 | All further doses should be held, till Xa <0.5 unit/ml | Restart at 60% of last dose | every 12 hrs until <0.5 unit/ml |
15.4 Monitoring
- Baseline labs-CBC, Chem 7
- Dosage adjustments should be made for CrCl < 30 mL/min ( dose once daily instead of q 12 hours)
- CBC should be checked 24 hours after initiation and upon restart of therapy. Then, every 2 or 3 days from Day 4 through Day 14 of therapy for signs of heparin induced thrombocytopenia.
15.5 Warfarin Bridging
- Overlap warfarin for at least 4-5 days AND until 2 therapeutic INRs on separate days are achieved
Adapted from https://www.universityhealthsystem.com/~/media/files/clinical-pathways/01-enoxaparin-pediatric-protocol.pdf?la=en
References
Monagle, P., E. Chalmers, A. Chan, G. deVeber, F. Kirkham, P. Massicotte, and A. D. Michelson. 2008. “Antithrombotic therapy in neonates and children: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition).” Chest 133 (6 Suppl): 887S–968S.
Wiltrout, Kayla, Jennifer Lissick, Mike Raschka, Amanda Nickel, and Dave Watson. 2020. “Evaluation of a Pediatric Enoxaparin Dosing Protocol and the Impact on Clinical Outcomes.” The Journal of Pediatric Pharmacology and Therapeutics : JPPT : The Official Journal of PPAG 25 (8): 689–96. https://doi.org/10.5863/1551-6776-25.8.689.