Low-Molecular-Weight Heparin Prophylaxis Dosing

Abstract

Objective. To evaluate the pharmacokinetic, safety, and effectiveness data of dosing low-molecular-weight heparins (LMWHs) for prophylaxis of venous thromboembolic events (VTEs) in obese people. Data Sources. A PubMed search (1966 to September 2015) was performed of published English articles using the following keywords: low-molecular-weight heparin, prophylaxis, and obesity. Study Selection and Data Extraction. In all, a total of 11 articles were included in this review. The search was conducted to identify pharmacokinetic studies, clinical trials (phases I-IV), or retrospective evaluations of the impact of weight and/or obesity on anti-Xa levels as well as the safety and effectiveness of LMWHs used for VTE prophylaxis. Data Synthesis. The vast majority of the available data focus on enoxaparin. Pharmacokinetic, effectiveness, and safety data all support increased enoxaparin dosing in obese patients. However, the optimal adjustment remains uncertain. For now, we recommend using 40 mg twice daily as the data for effectiveness use this regimen. Dalteparin dosing should not be adjusted in class I-II obese (body mass index 30.0-39.9 kg/m²) patients. Data regarding the impact of class III obesity (body mass index ≥40 kg/m²) on dalteparin effectiveness is needed. Total body weight dosing of tinzaparin can be used to optimize anti-Xa levels, but safety and effectiveness data are needed before weight-based tinzaparin dosing is routine medical practice for obese patients. Conclusions. The data regarding dosing of LMWHs for VTE prophylaxis are quite limited. High-quality studies are needed to help optimize dosing for obese adults requiring LMWH prophylaxis.