Nierfalen na bortezomib en erytromycine: Een nieuwe interactie?

Objective: This case report describes renal failure in a 71 year old male with multiple myeloma, stage IIA, after administration of bortezomib and erythromycin. We considered the possibility of an interaction between bortezomib and erythromycin. Design and methods: Description of the case and literature search. Results: During the first cycle of bortezomib, the patient showed a decrease in renal clearance (creatinin increased from 150 to 370 μmol/l). Renal function recovered within a week. Bortezomib was then continued at a reduced dose of 50%. Two days before the fourth administration, the patient developed fever. Erythromycin was started (500 mg p.o. four times daily), creatinin was still 150 μmol/l. One week later, the patient developed renal failure (creatinin 541 μmol/l) and was diagnosed with tubulo-interstitial nephritis caused by bortezomib toxicity likely based on an interaction with erythromycin. There is no information about this interaction in literature, but its occurrence can be explained by effects on CYP3A4 metabolism. Erythromycin is a moderate CYP3A4 inhibitor and substrate and bortezomib is a CYP3A4 substrate. Conclusion: We recommend frequent monitoring (serum creatinin on day 3/4 and day 7/8) of renal function in patients during and after administration of bortezomib in combination with a CYP3A4 inhibitor.