Measuring Anti–Factor Xa Activity to Monitor Low-Molecular-Weight Heparin in Obesity: A Critical Review – Correction

In a critical review of the literature concerning measurement of anti–factor Xa activity for the purpose of monitoring low-molecular-weight heparin (LMWH) in patients with obesity, two numeric errors appeared, both in relation to manufacturer information for tinzaparin. The correct values are presented here.

In Table 2, which presents the manufacturers’ published peak anti–factor Xa concentrations with various LMWH regimens, the third regimen for tinzaparin, as shown in the last row of the table, should be 175 U/kg (not 150 U/kg).

In the section “Are the Pharmacokinetic Parameters Unpredictable in Patients with Obesity, Because of Either Intrinsic Variability or the Presence of Other Confounding Factors?” (page 43), the dosage cap for tinzaparin should be 18 000 U daily, not 28 000 U daily. The first two sentences of this section are reproduced here, for context:

The product monographs recommend caution in weight-based dosing for patients with body weight over 120 kg (enoxaparin),¹⁷ over 90 kg (dalteparin),¹⁸ or over 105 kg (tinzaparin).¹⁹ They also recommend capping the dosage of enoxaparin at 150 mg twice daily or 210 mg once daily,¹⁷ dalteparin at 18 000 U daily,¹⁸ and tinzaparin at 18 000 U daily.¹⁹