Two cases of acute renal hemorrhage undergoing maintenance hemodialysis after concurrent administration of cinacalcet.

We report here a rare complication of renal hemorrhage in 2 male patients under treatment with long-term hemodialysis subsequent to the administration of the calcimemetic agent, cinacalcet hydrochloride. The patients presented with flank pain, peripheral hypereosinophilia and severe anemia. Computed tomography revealed a massive subcapsular hematoma on the kidney. Extensive coagulation analyses were within normal ranges. They had not been administered new medication for their complications during the 6 months prior to admission, except for cinacalcet (Case 1, 14 days; Case 2, 13 days). A drug lymphocyte stimulating test for cinacalcet was positive in both cases. Eight percent of the patients in our hospital who were administered cinacalcet presented with complication of renal hemorrhage. Based on these findings, the final diagnosis was renal hemorrhage due to cinacalcet. They were treated conservatively because both the size of the hematoma and anemia improved. To the best of our knowledge, this is the first report concerning renal hemorrhage.