INVESTIGATION OF A POSSIBLE INTERACTION BETWEEN CIPROFLOXACIN AND CYCLOSPORINE IN RENAL-TRANSPLANT PATIENTS

Background. Bacterial infection is a common complication during the fi rst few months after renal transplantation, Ciprofloxacin, a fluoroqui nolone broad-spectrum antibiotic, is used frequently in treating infec tions in the early posttransplant period, Evidence from in vitro studi es has suggested that ciprofloxacin can antagonize the cyclosporine (C sA)-dependent inhibition of interleukin-2 production. Such an effect i n renal transplant patients could antagonize the immunosuppressive act ivity of CsA and lead to rejection of the graft. Methods. To investiga te the possibility of a pharmacodynamic interaction between ciprofloxa cin and CsA, Ne conducted a case-control study in 42 patients who had received a kidney transplant and who were prescribed ciprofloxacin in the first 1-6 months after transplantation and in their matched contro ls (two per case) who did not receive ciprofloxacin during the study p eriod. Results. There was a twofold greater incidence (P = 0.008) of c iprofloxacin use at 1-3 months (65%) than was observed at 4-7 months ( 35%) after transplantation, The proportion of cases experiencing at le ast one episode of biopsy-proven rejection 1-3 months posttransplant ( 45%) was significantly greater (P = 0.004) than that of controls (19%) . Furthermore, there was a marked increase (P < 0.001) in the incidenc e of rejection temporally associated with ciprofloxacin use among case s (29%) compared with that experienced by the controls (2%). Conclusio ns, The possibility that ciprofloxacin increases rejection rates in re nal transplant patients may be of clinical importance and therefore wa rrants further investigation.