Implications of Clinical Mycophenolate Mofetil Dose According to Individual Body Weight in Japanese Renal Transplant Recipients

Abstract

BackgroundMycophenolate mofetil (MMF) is generally administered at a fixed dose of 0.5–1.5 g/d without considering individual body weight (BW) in Japanese renal transplant outpatients receiving maintenance therapy. We aimed to investigate the implications of the area under the curve of mycophenolic acid (MPA AUC):MMF dose ratio by individual BW and suggest the index of MMF dose according to individual BW. MethodsForty-three Japanese patients who received a renal transplant ≥6 months before the study were enrolled. Blood samples were collected at 4 time points: at predose, 20 minutes, 1 hour, and 3 hours after MMF administration. ResultsThe mean ± standard deviation MMF dose, MPA AUC, and BW of all patients were 581 ± 207 mg/d, 36.2 ± 18.7 μg·h/mL, and 56.3 ± 11.1 kg, respectively. Patients with a lower BW tended to have a higher MPA AUC:MMF dose ratio than patients with a higher BW. There was a significant correlation between the MMF dose:BW ratios and MPA AUC (r2 = 0.330; P < .01). The rate of MPA AUC between 30 and 60 μg·h/mL with the MMF dose:BW ratio of 10–16 mg/kg was 73.7%. ConclusionIndividual BW seems to affect the MPA AUC:MMF dose ratio; therefore, we need to consider individual BW when deciding on a MMF dose. The MMF dose:BW ratio of 10–16 mg/kg could predict MPA AUC between 30 and 60 μg·h/mL with a probability of approximately 75%. Therefore, it could be a useful index for outpatients, because it is difficult to draw blood frequently from such patients.