Therapeutic drug monitoring of once daily gentamicin in serum and saliva of children

Gentamicin is widely used in paediatric medicine and therapeutic monitoring is mandatory due to the narrow margin of safety. Saliva sampling may be of potential interest, especially in children in whom blood sampling is often difficult. Experience with once daily intravenous administration of aminoglycosides has grown in recent years. Gentamicin levels were measured in serum and saliva of 55 children treated with the drug (5 mg/kg per day), administered intravenously in three different regimens: thrice (n = 19), twice (n = 18), and once daily (n = 18). No correlation was found between serum gentamicin concentrations and saliva levels when the drug was administered twice or thrice daily, however, there was good correlation when the drug was administered once daily (r² = 0.96, P < 0.0001). Conclusion: In children with uncomplicated infections treated with once daily gentamicin, trough concentrations of the drug can be monitored in saliva.