skip to main content

Carbamazepine CYP3A4 Induction Tacrolimus — ESENeph MCQ

Instant feedback + full explanation. One question, done properly.

ModerateTransplantationCarbamazepine CYP3A4 Induction TacrolimusESENeph

A kidney transplant recipient on Tacrolimus develops new-onset seizures. His Tacrolimus trough is 6 ng/mL (within range). MRI brain is normal. EEG shows generalised epileptiform activity. He is started on Carbamazepine. Two weeks later his Tacrolimus trough drops to 2 ng/mL and creatinine rises. What happened?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: B — Carbamazepine is a CYP3A4 inducer that dramatically increases Tacrolimus metabolism, reducing blood levels and risking rejection – alternative anticonvulsants without CYP3A4 induction (Levetiracetam, Sodium Valproate) should be used

Carbamazepine (and Phenytoin, Phenobarbital) are potent CYP3A4 inducers that accelerate Tacrolimus metabolism, reducing trough levels by 50-80%. This can precipitate acute rejection. Levetiracetam is the preferred anticonvulsant in transplant recipients – it is not metabolised by CYP enzymes, has no significant drug interactions with immunosuppressants, and is renally excreted (dose adjustment needed in CKD). Sodium Valproate is an alternative but has hepatotoxicity and teratogenicity concerns. If Carbamazepine must be used, Tacrolimus dose increase with frequent level monitoring is essential.

Reference: BNF 2024 – Tacrolimus Interactions; KDIGO 2009 – Transplant