Tacrolimus toxicity in islet transplantation due to interaction with macrolides

BACKGROUND: Drug interactions are an important risk in transplant patients. Case presentation: This case describes an incident where a patient with islet transplantation, who was using tacrolimus as part of the immunosuppressant regime, was started on a course of clarithromycin and experienced nephrotoxicity and neurotoxicity. He was an outpatient at that time and was managed with temporary cessation of tacrolimus until the tacrolimus level returned to target and his symptoms resolved. He recovered well and was resumed on his usual dosage of tacrolimus to prevent rejection of islets. CONCLUSION: Care should be taken with commonly used antibiotics to avoid potentially dangerous interactions with immunosuppressant drugs.