Monitoring of Antibiotic Blood Levels (for Children Beyond the Neonatal Period) When gentamicin is used for synergy, a reasonable dose is 3 to 6 mg/kg per day in children and is adjusted for a target peak blood concentration of 3 to 4 g/mL and a trough of <1 g/mL. A dose of up to 7.5 mg/kg per day may be required for treatment of Gram-negative rod isolates, with peak blood levels of 5 to 10 g/mL and troughs of <1 to 1.5 g/mL. The daily dose is divided into 3 doses and given every 8 hours. Currently, there is insufficient clinical experience for treat- ment of pediatric IE with single daily dosing. For vancomy- cin, a starting dose for children is 40 to 60 mg/kg per day, and only trough concentrations are used for monitoring. The target trough blood level is usually 10 to 15 g/mL, although a higher blood level, 15 to 20 g/mL, may be required to treat methicillin/oxacillin/nafcillin-resistant staphylococci with a vancomycin MIC of >1 g/mL or when there is a lack of microbiological response. Children with renal failure require dosage adjustments, and in these cases, guidance from phar- macists, infectious diseases, or renal diseases consultants is recommended. Recommendations 1. When gentamicin is used for synergy, it is reason- able to give a dose of 3 to 6 mg/kg per day (divided as an every 8-hour regimen) in children, adjusted for a target peak blood concentration of 3 to 4 g/ mL and a trough of <1 g/mL (Class IIa; Level of Evidence B). Baltimore et al Infective Endocarditis in Childhood: 2015 Update 1505 2. Currently, there is insufficient clinical experience for treatment of pediatric IE with single daily dos- ing (of gentamicin) (Class III; Level of Evidence C). 3. 