Common anticoagulant therapies for use in pediatric VTE1,14,15
| Drug name . | Mechanism of action . | Pharmacokinetic properties and dosing . | Therapeutic monitoring (based on adult ranges) . | |
|---|---|---|---|---|
| UFH | Binds to AT and potentiates anticoagulant activity. The heparin-AT complex inactivates factors IIa (thrombin), Xa, XIa, and XIIa. | Half-life 0.5-2.5 h | Target range: aPTT: 1.5-2.5 times control OR UFH anti-Xa level: 0.3-0.7 U/mL | |
| Route: Continuous infusion | ||||
| Initial dose: | ||||
| Age <12 mo: bolus 75 U/kg followed by 28 U/kg/h | ||||
| Age >1-<12 y: bolus 75 U/kg followed by 20 U/kg/h | ||||
| Age >12 y: bolus 80 U/kg followed by 18 U/kg/h | ||||
| Enoxaparin (LMWH) | Binds to AT and potentiates anticoagulant activity. Has a reduced inhibitory activity against factor IIa (thrombin) relative to factor Xa. | Half-life 3-6 h, renal clearance | Target range: Enoxaparin anti-Xa peak: 0.5-1 U/mL (drawn 3-4 h after third dose) | |
| Route: Subcutaneous injection | ||||
| Initial dose: | ||||
| Age <2 mo: 1.5-1.7 mg/kg q12 h | ||||
| Age >2 mo: 1 mg/kg q12 h | ||||
| Dalteparin (LMWH) | Similar to enoxaparin. | Half-life 3-6 h, renal clearance | Target range: Dalteparin anti-Xa peak: 0.5-1 U/mL (drawn 3-4 h after third dose) | |
| Route: Subcutaneous injection | ||||
| Initial dose: | ||||
| Age 1 mo-<2 y: 150 IU/kg q12 h | ||||
| Age 2-<8 y: 125 IU/kg q12 h | ||||
| Age 8-<17 y: 100 IU/kg q12 h | ||||
| Fondaparinux | Synthetic pentasaccharide that binds AT and enhances inactivation of factor Xa. No inhibitory activity against factor IIa. | Half-life 17 h | Target range: Fondaparinux anti-Xa 0.5-1 mg/L (drawn 3-4 h after third dose) | |
| Route: Subcutaneous injection | ||||
| Initial dose: | ||||
| Age >1 y: 0.1 mg/kg q24 h | ||||
| Warfarin | Interferes with the cyclic conversion of vitamin K through the inhibition of vitamin K epoxide reductase. Resultant decrease in the posttranslational γ-carboxylation of vitamin K–dependent clotting factors II, VII, IX, and X and anticoagulants protein C and S. | Half-life 20-60 h | Target range: INR: 2-3 | |
| Route: Oral | ||||
| Loading dose: 0.2 mg/kg × 1 (if INR <1.3) (maximum, 10 mg) | ||||
| Check INR daily (days 2-4) and if the INR is: | ||||
| 1.1-1.3 | Repeat loading dose | |||
| 1.4-1.9 | 50% of loading dose | |||
| 2.0-3.0 | 50% of loading dose | |||
| 3.1-3.5 | 25% of loading dose | |||
| >3.5 | Hold until INR <3.5, restart at 50% loading dose | |||
| Drug name . | Mechanism of action . | Pharmacokinetic properties and dosing . | Therapeutic monitoring (based on adult ranges) . | |
|---|---|---|---|---|
| UFH | Binds to AT and potentiates anticoagulant activity. The heparin-AT complex inactivates factors IIa (thrombin), Xa, XIa, and XIIa. | Half-life 0.5-2.5 h | Target range: aPTT: 1.5-2.5 times control OR UFH anti-Xa level: 0.3-0.7 U/mL | |
| Route: Continuous infusion | ||||
| Initial dose: | ||||
| Age <12 mo: bolus 75 U/kg followed by 28 U/kg/h | ||||
| Age >1-<12 y: bolus 75 U/kg followed by 20 U/kg/h | ||||
| Age >12 y: bolus 80 U/kg followed by 18 U/kg/h | ||||
| Enoxaparin (LMWH) | Binds to AT and potentiates anticoagulant activity. Has a reduced inhibitory activity against factor IIa (thrombin) relative to factor Xa. | Half-life 3-6 h, renal clearance | Target range: Enoxaparin anti-Xa peak: 0.5-1 U/mL (drawn 3-4 h after third dose) | |
| Route: Subcutaneous injection | ||||
| Initial dose: | ||||
| Age <2 mo: 1.5-1.7 mg/kg q12 h | ||||
| Age >2 mo: 1 mg/kg q12 h | ||||
| Dalteparin (LMWH) | Similar to enoxaparin. | Half-life 3-6 h, renal clearance | Target range: Dalteparin anti-Xa peak: 0.5-1 U/mL (drawn 3-4 h after third dose) | |
| Route: Subcutaneous injection | ||||
| Initial dose: | ||||
| Age 1 mo-<2 y: 150 IU/kg q12 h | ||||
| Age 2-<8 y: 125 IU/kg q12 h | ||||
| Age 8-<17 y: 100 IU/kg q12 h | ||||
| Fondaparinux | Synthetic pentasaccharide that binds AT and enhances inactivation of factor Xa. No inhibitory activity against factor IIa. | Half-life 17 h | Target range: Fondaparinux anti-Xa 0.5-1 mg/L (drawn 3-4 h after third dose) | |
| Route: Subcutaneous injection | ||||
| Initial dose: | ||||
| Age >1 y: 0.1 mg/kg q24 h | ||||
| Warfarin | Interferes with the cyclic conversion of vitamin K through the inhibition of vitamin K epoxide reductase. Resultant decrease in the posttranslational γ-carboxylation of vitamin K–dependent clotting factors II, VII, IX, and X and anticoagulants protein C and S. | Half-life 20-60 h | Target range: INR: 2-3 | |
| Route: Oral | ||||
| Loading dose: 0.2 mg/kg × 1 (if INR <1.3) (maximum, 10 mg) | ||||
| Check INR daily (days 2-4) and if the INR is: | ||||
| 1.1-1.3 | Repeat loading dose | |||
| 1.4-1.9 | 50% of loading dose | |||
| 2.0-3.0 | 50% of loading dose | |||
| 3.1-3.5 | 25% of loading dose | |||
| >3.5 | Hold until INR <3.5, restart at 50% loading dose | |||
q, every.