Christine E. Staatz, Sophie Paviour, Stefanie Hennig
School of Pharmacy, University of Queensland, Brisbane 4072 Australia
Objectives: The aim of this study was to characterise current intravenous tobramycin monitoring and dosage adjustment practices in cystic fibrosis (CF) patients in Australia and the United Kingdom (UK) and compare practices between the countries.
Methods: An anonymous, online survey of health professionals caring for CF patients was conducted between November and December 2012. Survey questions were designed to obtain information on tobramycin dosing, therapeutic drug monitoring and toxicity monitoring.
Results: An online survey was sent to 232 CF health professionals. A response rate of 29.4% and 33.3% and was achieved from Australian and UK recipients respectively. Once daily dosing of tobramycin was the preferred administration regimen for 93.8% and 67.5% of CF health professionals in Australia and the UK respectively. 68.8% of Australian CF health professionals and 55% of UK health professionals initiated tobramycin therapy at a dose of 10mg/kg/day or greater. Tobramycin dosage was most commonly adjusted through calculation of tobramycin area-under-the concentration-time curve (AUC) using linear regression analysis in Australia and by use of tobramycin trough concentration measurements in the UK (See Table below).
Percentage breakdown of Dosage Adjustment Methods used across Countries
|
|
Australia |
United Kingdom |
|
Linear regression analysis |
40.6% |
0% |
|
Bayesian forecasting |
9.4% |
2.5% |
|
Trough concentration measurement |
25% |
55% |
|
Peak and trough concentration measurement |
6.3% |
37.5% |
|
Nomogram |
3.1% |
5% |
|
12-hour post-dose measurement |
3.1% |
0% |
|
Respondent unsure |
12.5% |
0% |
To monitor for nephrotoxicity, serum creatinine concentrations were routinely measured several times during admission by 62.5% of CF health professionals in Australia and 77.5% of CF health professionals in the UK. Ototoxicity monitoring was never routinely undertaken by 34.4% of CF health professionals in Australia and 35% of CF health professionals in the UK.
Conclusions: Health professionals in Australia are more likely to dose tobramycin once daily, use a higher initial dose of tobramycin and adjust tobramycin dosage according to an AUC estimate than those in the UK. Routine nephrotoxicity monitoring is more commonly undertaken in the UK, routine ototoxicity monitoring is not done by approximately 35% of CF health professionals in both countries.
Reference: PAGE 23 (2014) Abstr 3141 [www.page-meeting.org/?abstract=3141]
Poster: Drug/Disease modeling - Infection