CLINICAL RELEVANCE OF THERAPEUTIC DRUG-MONITORING OF DIGOXIN AND GENTAMICIN IN THE SALIVA OF CHILDREN

Digoxin and gentamicin are widely used in pediatric medicine, and ther apeutic monitoring is mandatory because of their narrow margin of safe ty and wide interpatient and intrapatient pharmacokinetic variabilitie s. Saliva sampling may be of potential interest, especially in childre n, in whom blood sampling is often difficult. In 11 children treated w ith digoxin for various cardiac conditions, and in 24 children treated with gentamicin (14 patients were administered gentamicin three times a day, and 10 once-daily), drugs levels were measured in plasma and s aliva. There was no correlation between plasma total or free digoxin c oncentrations and saliva levels, precluding the clinical use of the sa liva test for digoxin. No correlation was found between plasma gentami cin concentrations and saliva levels when the drug was administered th ree times a day; however: good correlation was found when the drug was administered once-daily (r(2) = 0.89, p < 0.0001). Saliva may be used as a noninvasive method of measuring gentamicin serum concentrations to guide dosage adjustments in patients administered the drug once-dai ly.