Older published guidelines have suggested DOACs, including apixaban, should be avoided in patients weighing >120 kg (264 lb). The recent 2021 ISTH guidelines suggest that standard doses of apixaban or rivaroxaban are among appropriate anticoagulation options regardless of high BMI and weight for the treatment of VTE.

Dose adjustment (per product label) is not necessary with apixaban in overweight or obese patients.

Obesity has modest effects on the pharmacokinetics of apixaban in healthy volunteers and in patients with NVAF. Exposure (per AUC) was decreased by 23% in healthy volunteers weighing > 264 lb versus 12% weighing 143 to 187 lb. In 2804 patients with NVAF in the ARISTOTLE trial, body weight accounted for only 21% of the variance in AUC.

Weight does not appear to influence the relationship between apixaban plasma concentration and its direct biological effect (anti-factor Xa activity).

In Phase 3 RCTs, patients as heavy as 204.9 kg (450.8 lb) and 210 kg (462 lb) were included in the ARISTOTLE (NVAF) and AMPLIFY (VTE treatment) trials.

Recently published RWD suggests the overall incidence of stroke or recurrent VTE was low in morbidly obese patients on apixaban, rivaroxaban, or warfarin; including those with BMI >50 kg/m².