Aminoglycosides in cystic fibrosis: a descriptive study of current practice in Australia

To determine the diversity of clinical practice with respect to aminoglycosides in cystic fibrosis (CF) units within Australia.

In April 1999, a questionnaire on the use of aminoglycosides was sent to 30 CF units across Australia. Information was collected about drug selection, dosing, monitoring and toxicity with intravenous administration.

Completed surveys were received from 26 of the 30 units (response rate = 86%) and all units with > 40 patients. Tobramycin was the drug of choice in all but two centres where there was equivalent use of gentamicin and tobramycin. The survey demonstrated a trend in recent years to reduce the number of doses per day with 54% of centres prescribing once daily, 23% twice daily and 23% thrice daily regimens. Initial dosing was generally based on mg/kg per day (mean 8.8, range 7.5-10 mg/kg per day). Dosing by infusion occurred in 11 of 14 units using once-daily dosing and there was equivalent use of bolus and infusion methods for multiple-daily regimens. Drug monitoring depended on dosing regimen. Units using multiple daily regimens monitored using trough +/- peak levels, whereas 50% of units using once-daily dosing used two postdose levels to alter dose. Actual toxicity, in particular nephrotoxicity, ototoxicity and vestibular toxicity was reported by 19, 27 and 12% of units, respectively.

The prescribing, dosing and monitoring of aminoglycosides in CF across Australia varies greatly. This is likely to be due to a lack of definitive evidence as to the optimum use in this patient group.