Therapeutic Enoxaparin in the Morbidly Obese Patient: A Case Report and Review of the Literature.

Enoxaparin is a low molecular weight heparin commonly used in the treatment of venous thromboembolisms (VTEs); however, evidence on optimal empiric dosing recommendations are lacking in patients with morbid obesity. Utilization of an absolute dose cap, anti-Xa monitoring, and reduced empiric dosing are among the techniques used in this population. We describe a case of a morbidly obese man (body-mass index, BMI: 68.2 kg/m2, total body weight: 236 kg) who required therapeutic enoxaparin for suspected pulmonary embolism (PE) and critical limb ischemia as a bridge therapy during warfarin initiation. An initial empiric dose of 200 mg Q12 hours (0.85 mg/kg) resulted in an anti-Xa level of 1.01 IU/mL following the fifth dose, and no dose modification was deemed necessary. He experienced no adverse effects from treatment. This report adds to a growing body of evidence illustrating the need for reduced empiric weight-based doses of enoxaparin in the morbidly obese population and raises the question of whether dose capping is an appropriate practice in the clinical setting of morbidly obese patients with acute VTE.

International normalized ratio increase before warfarin-associated hemorrhage: brief and subtle.

OBJECTIVE: To determine the relationship between serial international normalized ratios (INRs) in patients who have been undergoing long-term anticoagulation and the onset of warfarin-associated bleeding complications. METHODS: The study cohort consisted of 2391 patients treated in the Anticoagulation Service at Brigham and Women's Hospital, Boston, Mass, from April 1999 through July 2003. For each patient with a bleeding event, we selected 2 controls who were matched for age, sex, indication for warfarin therapy, and duration of enrollment in our Anticoagulation Service. RESULTS: Warfarin-related hemorrhage occurred in 32 patients (1.3%). The mean +/- SD INRs at the time of the bleeding event or matched patient's event date (5.9 +/- 5.9 vs 2.3 +/- 0.7; P<.001) and the mean+/-SD last INRs before the bleeding event or matched patient's event date (3.0 +/- 1.2 vs 2.1 +/- 0.8; P<.001) were higher in the patients than in the controls. The last INRs before the bleeding event were obtained an average of 11.6 +/- 17.8 (mean +/- SD) days before the event in the patients and 18.3 +/- 28.0 (mean +/- SD) days before the matched date in the controls (P = .22). The mean second-to-last INRs were similar in both groups (2.8 +/- 2.1 vs 2.3 +/- 0.8; P = .11). When the INRs were plotted in relation to the time before the onset of bleeding, a marked increase in the patients' INRs was observed shortly before the bleeding began. CONCLUSIONS: Serial INRs are poor predictors of hemorrhagic events. There appears to be only a brief warning period during which a slightly elevated INR predicts an imminent bleeding event.