Background: The metabolism of tacrolimus is influenced by several medications when they are given concurrently. We report the interaction between tacrolimus and chloramphenicol in a renal transplant recipient.
Methods: An adolescent with vancomycin-resistant Enterococcus was given standard doses of chloramphenicol. Tacrolimus trough levels increased, and the dose was adjusted to maintain the target trough level. Pharmacokinetic studies were obtained during chloramphenicol administration and 14 days after its discontinuation.
Results: Toxic levels of tacrolimus were seen on the second day of chloramphenicol administration, requiring an 83% reduction in the tacrolimus dose. The dose-adjusted area under the curve value for tacrolimus was 7.5-fold greater while the patient was on chloramphenicol. These data are consistent with inhibition of tacrolimus clearance by chloramphenicol
Conclusions: Chloramphenicol interferes with tacrolimus metabolism. Careful monitoring of tacrolimus trough levels during concomitant chloramphenicol therapy is recommended to avoid toxicity.