Vancomycin trough plasma concentration monitoring in young infants and children

For intermittent vancomycin infusions in young infants aged 0 to 90 days, the recommended vancomycin target trough concentration ranges are listed in Vancomycin target trough concentration ranges in young infants treated with an intermittent infusion. The target trough concentration depends on the postmenstrual age and the dosing interval. The trough plasma concentration should be taken immediately before the dose is administered and measured at steady state; in most young infants steady state is reached after 24 to 48 hours of therapyGwee 2019.

Table 1. Vancomycin target trough concentration ranges in young infants treated with an intermittent infusion
Gwee 2019
Postmenstrual age [NB1]: less than 29 weeks 29 to less than 36 weeks 36 to 44 weeks more than 44 weeks
Postmenstrual age: less than 29 weeks
Dose interval	Target range [NB2]
6 hours [NB3]	not applicable
8 hours [NB4]	not applicable
12 hours	14 to 20 mg/L
24 hours	10 to 15 mg/L
Postmenstrual age: 29 to less than 36 weeks
Dose interval	Target range [NB2]
6 hours	15 to 20 mg/L
8 hours	13 to 20 mg/L
12 hours	13 to 20 mg/L
24 hours	8 to 15 mg/L
Postmenstrual age: 36 to 44 weeks
Dose interval	Target range [NB2]
6 hours	15 to 20 mg/L
8 hours	13 to 20 mg/L
12 hours	10 to 15 mg/L
24 hours	8 to 15 mg/L
Postmenstrual age: more than 44 weeks
Dose interval	Target range [NB2]
6 hours	15 to 20 mg/L
8 hours	10 to 15 mg/L
12 hours	8 to 15 mg/L
24 hours	8 to 15 mg/L
Note: NB1: Postmenstrual age = gestational age (time between the first day of the last menstrual period and birth) + postnatal age (time since birth). NB2: In situations where the risk of not achieving an area under the concentration–time curve over a 24-hour period (AUC₂₄) of 400 to 650 mg.hr/L is unacceptable (eg young infants who are critically ill or unstable), to increase the likelihood of achieving an AUC₂₄ of above 400 mg.hr/L, a trough concentration at the upper end of the trough target range may be preferred. NB3: A dose interval of 6 hours is not recommended for young infants with a postmenstrual age less than 29 weeks because the target trough concentrations required to achieve an AUC₂₄ above 400 mg.hr/L will exceed 20 mg/L. NB4: A dose interval of 8 hours is not recommended for young infants with a postmenstrual age less than 29 weeks because the target trough concentrations required to achieve an AUC₂₄ above 400 mg.hr/L for target attainment will exceed 20 mg/L.