From the Guidelines
Apixaban (Eliquis) is effective in women with severe obesity, with comparable efficacy and safety to warfarin, as demonstrated in recent studies 1. The pharmacokinetics of apixaban may be altered in morbid obesity, potentially affecting drug levels in the bloodstream. However, standard dosing of apixaban (typically 5 mg twice daily for most indications, or 2.5 mg twice daily for certain patients) appears to provide adequate anticoagulation in most morbidly obese patients, including women. Some key points to consider when using apixaban in severely obese women include:
- Monitoring anti-Factor Xa levels in patients with BMI >40 kg/m² or weight >120 kg to ensure adequate anticoagulation, although this is not universally recommended 1.
- Considering individual factors such as kidney function, drug interactions, and bleeding risk when selecting the appropriate anticoagulant.
- Being aware that some experts might prefer vitamin K antagonists like warfarin in extreme obesity (>150 kg), where levels can be more easily monitored through INR testing. Recent studies, including a retrospective study by Cohen et al 1 and a systematic review and meta-analysis by Mhanna et al 1, have demonstrated the efficacy and safety of apixaban in severely obese patients with atrial fibrillation or venous thromboembolism. Overall, apixaban remains a reasonable option for morbidly obese women with atrial fibrillation or venous thromboembolism requiring anticoagulation, with careful consideration of individual factors and monitoring as needed.
From the Research
Efficacy of Apixaban in Women with Severe Obesity
- The efficacy of apixaban in women with severe obesity is not directly addressed in the provided studies, as they do not specifically focus on the female population or compare outcomes between genders 2, 3, 4, 5, 6.
- However, the studies suggest that apixaban is effective in obese patients with nonvalvular atrial fibrillation, regardless of gender, with similar rates of stroke, transient ischemic attack, myocardial infarction, and atrial thrombosis compared to non-obese patients 2, 3, 5.
Safety of Apixaban in Obese Patients
- The safety of apixaban in obese patients is evaluated in several studies, which report that apixaban is associated with a similar or lower risk of major bleeding compared to warfarin in obese patients with nonvalvular atrial fibrillation 3, 5.
- One study found that apixaban exposure did not vary substantially between obese and normal-weight matched controls, implying that general dose adjustments are not required 6.
- However, another study noted that the variability in trough concentration was considerably higher in patients with obesity, suggesting that measuring concentrations could be valuable for specific patients 6.
Pharmacokinetics of Apixaban in Obese Patients
- The pharmacokinetics of apixaban in obese patients are reviewed in one study, which suggests that obesity does not substantially influence the efficacy, effectiveness, or safety of apixaban in patients with nonvalvular atrial fibrillation or venous thromboembolism 4.
- Another study found that apixaban plasma concentrations in patients with obesity were similar to those in patients with normal weight, with slightly higher trough concentrations in obese patients 6.