Determining gentamicin dosage in infants and children with renal failure.

Gentamicin half-life values based on pharmacologic calculations were determined in 23 infants and children with diminished renal function. The half-life times correlated significantly with serum creatinine concentrations in patients who had steady-state creatinine levels (Y = 0.379 + 3.841 X, R = 0.951, P less than 0.001). This relationship provides a basis for formulating gentamicin dosage in pediatric patients with renal failure. The half-life of gentamicin is estimated by multiplying the serum creatinine concentration by four; three-quarters of the loading dose is administered every two half-lives. When renal function is unstable and changing daily, gentamicin half-life cannot be reliably predicted from the serum creatinine value.