Mizoribine requires individual dosing due to variation of bioavailability

    loading  Checking for direct PDF access through Ovid



Mizoribine (MZR) is an immunosuppressant used for the treatment of glomerular diseases, but there are few reports on the pharmacokinetics of MZR in children.


First, we performed a pharmacokinetic study on nine childhood-onset glomerular disease patients. The MZR dosages ranged from 1.8 to 14.5 mg/kg/dose. Pharmacokinetic parameters were analyzed using 38 MZR concentration-time curves. Second, nine patients who were newly treated with MZR were enrolled to validate the findings obtained from prior investigation.


In the prior study, peak serum MZR concentration (Cmax) was dose-dependent in each patient. Although proportionality between dosage and Cmax was observed in each patient, the regression coefficient was in a wide range from 0.075 to 1.04 and was specific to each patient. This variability was likely caused by individual variation of bioavailability. When the optimal time-point to monitor Cmax was investigated, the time-to-reach peak serum MZR concentration (Tmax) was similar among all the patients, which was from 2.5 to 3.5 h after administration of MZR. Tmax was most frequently observed at 3 h and the serum MZR concentration ratio relative to Cmax at 3 h was also highest (0.93 ± 0.07). In the following study, it was validated that monitoring C3 is reproducible and reliable after adjusting the dosage of MZR to obtain target serum concentration.


Individual dosing is required to optimize Cmax in childhood-onset glomerular disease patients. The safe dosage of MZR for each patient could be predicted by evaluating the serum MZR concentration 3 h after administration.

Related Topics

    loading  Loading Related Articles