Long-term effect of chronic intravenous and inhaled nephrotoxic antibiotic treatment on the renal function of patients with cystic fibrosis.

Cystic fibrosis (CF) patients have numerous infectious exacerbations requiring prolonged antibiotic treatments, some of which are nephrotoxic. Inhaled antibiotics can reach detectable serum levels. We studied the impact of chronic nephrotoxic antibiotic exposure on kidney function in CF population. We collected data retrospectively for 113 adult CF patients followed for 8.5 years. Fifty-seven (50.4%) were males and 56 (49.5%) females (mean age 31.7 years [SD 9.9]), of which 31% had diabetes and 9.7% had hypertension. Over 8.5 years follow up, there were no significant changes in blood urea nitrogen (BUN; P = 0.92) or creatinine (P = 0.2) in the whole group. 22% of patients had ≥1 episodes of acute kidney injury (AKI). The presence of AKI was associated with increased BUN (P = 0.002) and creatinine (P = 0.056) at the end of follow up. Use of intravenous colistin, gentamicin, tobramycin, or vancomycin did not correlate with increased BUN (P = 0.64; P = 0.49; P = 0.51; P = 0.47) or creatinine (P = 0.43; P = 0.49; P = 0.17; P = 0.2) after 8.5 years. Elevated tobramycin peak and trough levels did not correlate with increased BUN or creatinine. Inhaled colistin and gentamicin correlated with increased BUN (P = 0.009; P = 0.02) but not creatinine (P = 0.45; P = 0.46). Inhaled tobramycin did not correlate with increased BUN (P = 0.17) or creatinine (P = 0.58). Only inhaled colistin correlated with AKI episodes (P = 0.03). Chronic inhaled colistin and gentamicin are associated with an increase in BUN but not creatinine at the end of follow up. Inhaled colistin was associated with episodes of AKI. Well-managed intravenous use of nephrotoxic antibiotics in CF population is associated with no major long-term renal toxicity.