Comparing weight-based dosing of tacrolimus XR in obese and non-obese renal transplant recipients.

The recommended initial weight-based dose of extended-release (XR) tacrolimus (Envarsus XR) in kidney transplant recipients (KTR) is 0.14 mg/kg/day. However, no data exist regarding dosing recommendations for obese patients specifically. The aim of this study was to evaluate weight-based dosing requirements in a cohort of obese KTR who were initiated on de novo tacrolimus XR post-transplantation. The primary outcome was weight-based dosing requirements (mg/kg/day) on post-operative day (POD) 7 and 14. Of the 254 KTR, 81 (31%) were obese. The median therapeutic dose on POD7 was 0.1 versus 0.12 vs. 0.14 mg/kg/day in the BMI > 30 kg/m2 , BMI 25-30 kg/m2 , and BMI < 25 kg/m2 , respectively, (p = .0001). This result was similar on POD14; median therapeutic dose was 0.09 versus 0.11 versus 0.15 mg/kg/day in the BMI > 30 kg/m2 , BMI 25-30 kg/m2 , and BMI < 25 kg/m2 , respectively, (p < .001). Therapeutic dose on POD7 and POD14 based on ideal body was similar in all cohorts (p = .238, p = .923, respectively). This finding was supported by a strong linear relationship between ideal body weight (IBW) and therapeutic dose (r = .929). In both obese and non-obese KTR, IBW had a stronger correlation with the therapeutic dose for tacrolimus XR.