Pharmacokinetics of intravenous/subcutaneous enoxaparin in patients with acute coronary syndrome undergoing percutaneous coronary interventions

Plasma anti-Xa activity after Enoxaparin administration in patients with acute coronary syndrome (ACS) undergoing coronary angiography and percutaneous coronary intervention (PCI) has not been well established. Patients presenting with non-ST-elevation ACS received an initial dose (0.75 mg/kg) of Enoxaparin intravenously (IV), with subsequent doses (1 mg/kg) subcutaneously (SC) beginning 8 hr following the IV dose. Patients who underwent PCI within 4 hr of the IV dose or 8 hr of the SC dose did not receive additional Enoxaparin. All others received 0.3-0.4 mg/kg additional IV Enoxaparin at the time of PCI. All patients undergoing PCI received a glycoprotein IIb/IIIa inhibitor and clopidogrel. Mean plasma anti-Xa activity (units/ml) 10 min and 2, 4, 6, and 8 hr after IV dose was 2.29 +/- 0.39, 0.99 +/- 0.295 0.58 +/- 0.14, 0.36 +/- 0.13, 0.24 +/- 0.11, respectively. Mean Plasma anti-Xa activity 2, 4, 6, 8, 10, and 12 hr after SC dose was 1.01 +/- 0.22,1.13 +/- 0.27, 1.1 +/- 0.41, 0.84 +/- 0.195 0.62 +/- 0.24, and 0.46 +/- 0.21, respectively. Mean plasma anti-Xa activity at the start and end of PCI was 1.27 +/- 0.41 and 1.07 +/- 0.42, respectively. In conclusion, adequate anticoagulation with Enoxaparin may be achieved within 10 min after an IV dose of 0.75 mg/kg. High-risk ACS patients requiring urgent PCI may benefit from this approach. PCI may be performed without additional anticoagulation within 4 hr of IV or 8 hr of SC Enoxaparin. PCI 4-8 hr after IV dose or 8-12 hr after SC dose will require additional IV Enoxaparin 0.3-0.4 mg/kg to ensure therapeutic anti-Xa activity.