High-Dose, Extended-Interval Gentamicin and Tobramycin for Pediatric Inpatients: A Survey of Canadian Hospital Pharmacists

Abstract

The use of high-dose, extended-interval aminoglycosides, a common practice in adult populations, is less well established for pediatric patients. In younger populations, these drugs are often administered according to a multiple daily dosing method. To characterize prescribing practices for aminoglycosides in pediatric inpatients across Canada, with a focus on high-dose, extended-interval regimens. This study was based on an electronic survey of pharmacists representing Canadian health care delivery organizations that provided pediatric inpatient services, which was distributed in March 2015. Questions focused on demographic characteristics; indications for high-dose, extended-interval tobramycin or gentamicin; use of these regimens in patients with particular comorbidities; empiric dosing; monitoring parameters; and the extent of pharmacists' authority to independently prescribe doses and order monitoring parameters for aminoglycosides at their respective institutions. Forty-five (48%) of the 94 prospective participants responded to the survey. Of these 45 respondents, 35 (78%) indicated that their respective health regions used high-dose, extended-interval tobramycin or gentamicin in pediatric inpatients. The patient characteristics for use of such regimens were varied. The median reported doses were 10 mg/kg for pulmonary exacerbation in cystic fibrosis, 7 mg/kg for urinary tract infection, and 8 mg/kg for febrile neutropenia. Thirty-one (89%) of the 35 respondents using these regimens reported that they monitored serum levels, and 27 (77%) reported monitoring for nephrotoxicity. With regard to prescriptive authority, 7 (16%) of the 45 respondents indicated that pharmacists were authorized to independently adjust dosing at their institutions, and pharmacists at 14 (31%) of 45 sites were authorized to order monitoring parameters. High-dose, extended-interval aminoglycoside therapy was frequently used for pediatric patients across Canada, although the dosages and monitoring practices varied greatly. The information from this study can be used for cross-comparison of practice by other centres across Canada.