Caution with gentamicin in cystic fibrosis

Intravenous aminoglycoside antibiotics, especially gentamicin, raise the risk of acute kidney failure in people with cystic fibrosis (CF), so intravenous gentamicin is no longer recommended for treating chest flare-ups in CF, says Dr Alan Smyth of the University of Nottingham.

Using gentamicin within the past year was linked with a higher risk of kidney failure, which wasn't seen with tobramycin. Moreover, about half of the Pseudomonas aeruginosa bacteria isolated from CF patients in the United States resist gentamicin.

Dr Smyth suggests treating chest flare-ups with ceftazidime and tobramycin. This was applied to 80 children with CF, whose kidney function was monitored with chromium-EDTA and linked with avoidable factors such as repeated aminoglycoside courses, NSAIDs and other kidney risk factors. Some have suggested giving aminoglycosides once a day, in the morning rather than the evening, to lower toxicity, but this needs more study.

The researchers concluded that kidney function should be checked carefully in CF patients before aminoglycoside treatment starts, and other kidney risk factors should be reduced while they are used. The study was published in Thorax in 2008.