Everolimus is an inhibitor of mammalian target of rapamycin (mTOR) widely used as an immunosuppressant in transplant patients. In transplantation setting, several recommendations for therapeutic drug monitoring are available, due to potential drug-drug interactions with chronic medication, which can affect everolimus pharmacokinetic profile. Everolimus is also used in breast, neuroendocrine and renal cancer, at higher doses than in transplantation and without systematic drug monitoring requirement. We present a case-report of a 72years-old woman with epilepsy history to whom everolimus 10mg/daily was prescribed as third line of treatment for renal cell carcinoma. The patient´s chronic medication was checked by the outpatient hospital pharmacist before initiating treatment. As a result, two major interactions with inducers of CYP3A4 metabolism as carbamazepine and phenytoin were detected. Since trough plasma concentration of everolimus could be affected, by these pharmacokinetic interactions,a therapeutic drug monitoring of everolimus was proposed. Based on the literature, Cmin plasma concentration (Cminss) of everolimus over 10ng/ml is associated with better response to treatment and progression free survival. During the oncologist follow-up visit and according to pharmaceutical recommendations, everolimus dosage was increased to 10mg every 12 hours. In the following determinations of trough plasma everolimus concentration, Cmin grow up from 3.7ng/ml to 10.8ng/mL. Depending on the CYP3A4 induction capacity and potency of the drug/s administered concomitant to everolimus and how many of them can potentially interact with it, therapeutic everolimus monitoring would be advisable in order to adjust dosage if required to prevent underexposure.