The Impact of Weight on Drug Dosing


Body Mass Index Tied to Warfarin Effectiveness

In another study, Julia A. Mueller, MD, of the Mayo Clinic in Jacksonville, FL, and colleagues evaluated the impact of body mass index (BMI) on total weekly dosing of warfarin, the most common treatment for venous thromboembolism and other hypercoagulable conditions. While previous studies have developed protocols for the dosing of warfarin, few studies have evaluated the impact of BMI on warfarin dosing due to risk of adverse events associated with underdosing and overdosing.

In this retrospective study, the investigators evaluated 831 patients and found a significant correlation between BMI and total weekly dosing of warfarin. Therefore, according to the authors, this could have dosing implications for both patients and prescribers because patients with a high BMI will be expected to require higher doses of warfarin to maintain effectiveness.3

Antibiotic Failure: A Weighty Issue in Patients with Obesity


Overall, in clinical practice, there remains uncertainty in how to dose certain medications in overweight and obese patients, especially with high-risk medications such as anticoagulants and sedatives. Therefore, according to Kane-Gill, further studies are required to help guide clinical practitioners to be more vigilant for therapeutic failures and adverse drug reactions in these patients.


1.      Centers for Disease Control and Prevention (CDC). Adult Obesity Facts. Available at: Accessed: May 18, 2014.

2.      Kane-Gill SL, Wytiaz NP, Thompson, LM, et al. A real-world, multicenter assessment of drugs requiring weight-based calculations in overweight, adult critically ill patients. Scientific World Journal. 2013; 1-9.

3.      Mueller JA, Patel T, Halawa A, et al. Warfarin dosing and body mass index. Annals of Pharmacotherapy. 2014: 48 (5); 584-588.