Intravenous aminoglycoside usage and monitoring of patients with cystic fibrosis in Australia. What's new?

BACKGROUND: The aim of this study was to determine the current situation regarding aminoglycoside use and monitoring in patients with cystic fibrosis (CF) throughout Australia.
METHODS: A questionnaire was sent out to all CF units. Information gathered included patient characteristics, aminoglycoside use, dosing, therapeutic drug-monitoring methods, toxicity monitoring and incidence of occurrence.
RESULTS: Responses were obtained from 27 of the 28 units identified. Tobramycin was the aminoglycoside of choice. All but three centres were using once-daily dosing for aminoglycoside administration. Initial dosing in tobramycin-naïve patients was based on bodyweight (range 7-12 mg/kg). Patients being readmitted were mainly prescribed the dose that they had received on their previous admission. All units gave i.v. doses by infusion with five units using bolus dosing as well. The method of therapeutic drug monitoring varied greatly. A computer programme was used by 15 units. Toxicity monitoring usually coincided with therapeutic drug monitoring. Nephrotoxicity was reported as having occurred in 13 units and ototoxicity in 15 units. The highest incidence of toxicity was ototoxicity in 20% of patients in one CF unit.
CONCLUSION: Aminoglycoside dosing regimens have changed since the last survey was carried out in 1999. There has been an increase in the use of once-daily dosing from 54 to 88% of units. The reporting of both ototoxicity and renal toxicity has also increased (from 27 to 75% and from 19 to 65%, respectively). Standardization of management protocols for antibiotic use and patient monitoring may help reduce the risk of cumulative toxicity to aminoglycosides in CF patients.