Effects of Atorvastatin on the Pharmacokinetics of Everolimus Among Kidney Transplant Recipients

Background. Hyperlipidemia occurs in up to 50% of kidney transplant (KT) recipients who take everolimus (EVL). As a result of this, statins are the most commonly prescribed lipid-lowering drugs among these patients. However, we are concerned whether there are any drug interactions between EVL and statins, because both of these drugs use the same pharmacokinetics pathway. Therefore, we assessed the effects of concomitant use of EVL and atorvastatin. Methods. In this randomized, open-label, crossover study, 20 KT patients were assigned (1:1) to receive EVL with or without 20 mg atorvastatin for 1 month. One-month washout period was used before crossover. Plasma EVL concentrations were measured by homogeneous particle-enhanced turbidimetric immunoassay. Twelve-hour area under the time-concentration curve (AUC(0-12)) of EVL was calculated with the use of whole-blood EVL concentrations from 10 different time points (0, 0.5, 1, 1.5, 2, 2.5, 4, 6, 8, and 12 hours). Results. The mean (SD) AUC(0-12) for EVL and EVL plus atorvastatin was 155.9 (41.6) ng.h/mL and 151.3 (51.4) ng.h/mL, respectively (P > .05; paired t test). No difference of EVL Cmax or Tmax was found after atorvastatin coadministration. Even though the EVL AUC(0-12) levels were not affected by atorvastatin coadministration in one-half of the subjects, for the rest of the patients, there were unpredictable changes in the EVL AUC(0-12) levels. This may be due to the high intrapatient variability of EVL drug concentration (coefficient of variation ranges from 9.8% to 34.1%). Conclusions. Coadministration of atorvastatin with EVL in KT recipients did not affect the pharmacokinetics of EVL.