RESUMEN
Pharmacologic prophylaxis of deep vein thrombosis and venous thromboembolism (VTE) is an important aspect of medical care, particularly in the inpatient setting. Low-molecular weight heparins, heparin, and fondaparinux are commonly used agents to prevent VTE, each of which has well established dosing regimens in patients with normal body mass index. Dosing of these medications in morbidly obese populations (BMI > 40 kg/m(2)) is not as clearly defined in guidelines. This article reviews published data to support specific dosing regimens and monitoring strategies of these agents in this population. The most validated parenteral agent to prevent VTE in morbidly obese hospitalized patients is enoxaparin, dosed at 40 mg subcutaneously (SC) twice daily. If unfractionated heparin is utilized for prophylaxis in morbidly obese patients, a dose of 7500 units SC three times daily should be considered. Monitoring of anti-factor Xa levels to guide prophylactic dosing is an option, although the utility of this lab test is limited, as target anti-Xa ranges for VTE prophylaxis have not been universally defined and trials have not shown a clear link between anti-factor Xa levels and bleeding or thrombotic events. Additional studies are needed to clearly define the most appropriate dosing strategies in patients with moderate obesity (BMI 35-40 mg/m(2)) and those with extreme obesity (BMI > 60 mg/m(2)).
Asunto(s)
Heparina/uso terapéutico , Obesidad Mórbida , Polisacáridos/uso terapéutico , Tromboembolia Venosa/prevención & control , Factor Xa/metabolismo , Femenino , Fondaparinux , Hemorragia/sangre , Hemorragia/inducido químicamente , Heparina/efectos adversos , Humanos , Masculino , Obesidad Mórbida/sangre , Obesidad Mórbida/complicaciones , Obesidad Mórbida/tratamiento farmacológico , Polisacáridos/efectos adversos , Tromboembolia Venosa/etiología , Trombosis de la Vena/sangre , Trombosis de la Vena/etiología , Trombosis de la Vena/prevención & controlRESUMEN
The effect of obesity on the pharmacokinetics of enoxaparin is not clearly understood and traditional treatment doses in morbidly obese patients (body mass index [BMI] > 40 kg/m(2)) can lead to over anticoagulation. Our institution developed an inpatient protocol with reduced enoxaparin doses (0.75 mg/kg/dose based on actual body weight) for patients with a weight >200 kg or BMI > 40 kg/m(2). The primary objective was to determine if modified enoxaparin treatment doses would achieve therapeutic anti-Xa levels (goal range 0.6-1.0 IU/mL) in morbidly obese patients. Thirty-one patients were included in our study and had a median body weight of 138 kg (range 105-197) and a median BMI of 46.2 kg/m(2) (range 40.1-62). The initial peak anti-Xa levels were in therapeutic range in 15 of 31 patients (48 %) with an initial mean anti-Xa level of 0.92 IU/mL. Twenty-four patients (77 %) achieved therapeutic anti-Xa levels in goal range during their hospitalization, with a mean enoxaparin dose of 0.71 mg/kg. Bleeding and thrombotic events were minimal and all patients that achieved an anti-Xa level in goal range did so with a dose less than 1 mg/kg of enoxaparin.