Title:Involvement of CYP 3A5 In the Interaction Between Tacrolimus and Nicardipine: A Case Report
Volume: 10
Issue: 3
Author(s): Mouna B. Sassi, Emna Gaies, Issam Salouage, Sameh Trabelsi, Mohamed Lakhal and Anis Klouz
Affiliation:
Keywords:
CYP 3A5, drug interaction, nicardipine, renal transplantation, tacrolimus, therapeutic drug monitoring.
Abstract: Tacrolimus is a calcineurin inhibitor primarily metabolized by CYP3A4 and secondarily by
CYP3A5. Several drugs can modify tacrolimus blood levels as calcium channel blockers (CCBs).
Interaction with nicardipine was reported in some cases.
A man with a history of malignant arterial hypertension treated with nicardipine, underwent kidney
transplantation. After transplantation, he was treated with tacrolimus, mycophenolate mofetil and
corticoids. Therapeutic drug monitoring of tacrolimus was done regularly showing a mean trough
concentration (C0) of 24.39 ng/mL with some concentrations reaching 52 ng/mL. After changing
nicardipine by prazosine, the first tacrolimus C0 after stopping nicardipine was 3.2 ng/mL.
Increase of tacrolimus trough concentrations is due to the inhibition of CYP3A4. Very high levels of tacrolimus suggest
the non expression of CYP3A5. Thus, because of the possible lack of the secondary pathway, therapeutic drug monitoring
of tacrolimus is highly recommended at the introduction of CCBs and also at its stopping.