Table 2 Dosing for antithrombin
From: Clinical controversies in anticoagulation monitoring and antithrombin supplementation for ECMO
| Â | Surgical dosing | Obstetrical dosing |
|---|---|---|
Plasma-derived AT concentrate [56] | ||
 Initial loading dose (IU) | ([desired % AT activity − baseline % AT activity] × body weight in kilograms) ÷ 1.4 Infuse IV over 10–20 min | Same formula |
 Maintenance dose (IU) | 60% of the initial loading dose, given every 24 h for 2–8 days | |
 Dose adjustments | Adjust maintenance dose and/or interval to maintain AT activity levels of 80–120% Measure AT activity levels 20 min postinfusion of initial dose, every 12 h, and before each infusion | |
Recombinant AT concentrate [57] | ||
 Initial loading dose (IU) | ([100 − baseline % AT activity] ÷ 2.3) × body weight (kg) Administer loading dose as a 15-min intravenous infusion and immediately follow it by a continuous infusion of the maintenance dose | ([100 − baseline % AT activity] ÷ 1.3) × body weight (kg) Administer initial dose as a 15-min intravenous infusion and immediately follow it by a continuous infusion of the maintenance dose |
 Maintenance dose (IU/h) | ([100 − baseline % AT activity] ÷ 10.2) × body weight (kg) given per hour | ([100 − baseline % AT activity] ÷ 5.4) × body weight (kg) given per hour |
 Dose adjustments | Adjust based on the % AT activity level 2 h after initiation of treatment For AT activity level < 80%, increase dose by 30% and recheck 2 h after each dose adjustment For AT activity level 80–120%, do not adjust and recheck 2–6 h after initiation of treatment or dose adjustment For AT activity level > 120%, decrease dose by 30% and recheck 2 h after each dose adjustment | |