Anticoagulant profile of subcutaneous enoxaparin in healthy dogs

Our study objective was to identify a subcutaneous enoxaparin dosage that provided a consistent anticoagulant intensity in dogs. Our hypotheses were that a dose of 0.8 mg/kg would provide inconsistent anticoagulation, a higher dose would provide consistent anticoagulation over a greater duration of time, and viscoelastometry would effectively monitor the anticoagulant status. Six healthy dogs received two subcutaneous enoxaparin doses (0.8 and 2 mg/kg) for anti-Xa activity determinations and pharmacokinetic modeling. Based on calculations derived from these results, 1.3 mg/kg, SC, q8 h was administered for seven doses. Target ranges for anticoagulant intensity were defined as anti-Xa activity of 0.5-1 U/ml, and change from baseline of two viscoelastometric parameters: activated clotting time (Delta ACT; >= 40 s), and clot rate (CRpost; <= 20 U/min). Following an initial injection at 1.3 mg/kg, anti-Xa activity of 5/6 dogs reached or exceeded the target range. Following the final dose, anti-Xa activity reached or exceeded the target range in all dogs, and Delta ACT and CRpost values exceeded target for 2-6 and 4-12 h, respectively. At an enoxaparin dosage of 1.3 mg/kg, SC, q8 h, anti-Xa activity was consistently above the minimum threshold of the target range; however, the safety of this dosage remains to be determined.