Gentamicin Blood Levels: a Guide to Nephrotoxicity

Abstract

Gentamicin blood levels were monitored in 86 patients. Twenty-one patients had valley levels over 2 ,ig/ml and 36% of these patients developed abnormal serum creatinine or a further rise in creatinine. No patient had a rise in creatinine without a valley level over 2. The peak levels in patients with valleys over 2 were above 10 ug/ml in only one case, whereas four patients had peaks over 10 4g/ml without nephrotoxicity. The mean peak blood levels in patients with a normal creatinine were dose related. An initial dose of 2.0, 1.5, and 1.3 or less mpk (mg/kg) yielded mean peak blood levels of 5.2, 4.7, and 3.7, respectively. To assure an initial peak blood level over 4 ug/ml a loading dose of 2 mpk was required. A rise in peak and valley levels during therapy appeared dose related, being observed in all patients treated with 4.5 mpk daily but not in those receiving 3.0 mpk daily. A radioenzymatic assay was used to validate the standard agar diffusion assay method. The results from the two assays were statistically identical. Valley blood levels of gentamicin may be useful for predicting accumulation of gentamicin which in tum may be correlated with early renal impairment before potentially toxic serum levels of gentamicin develop.

Gentamicin Pharmacokinetics in Term Newborn Infants Receiving High-Frequency Oscillatory Ventilation or Conventional Mechanical Ventilation: a Case-controlled Study

“…21 Persistent gentamicin trough concentrations greater than 2 mcg/ml have been associated with nephro-and ototoxicity. 22,23 Gentamicin is eliminated almost entirely by the kidneys, and its clearance mimics that of serum creatinine. 24 Thus, it is important to avoid high serum trough concentrations and to provide for adequate monitoring of gentamicin therapy in newborn infants at risk for developing renal dysfunction from such treatments.…”

Clinical Pharmacokinetics, Toxicity and Cost Effectiveness Analysis of Aminoglycosides and Aminoglycoside Dosing Services

“…There appears to be a correlation between increased trough concentrations of gentamicin and nephrotoxicity (27,73). Trough concentrations of more than 2 mg/l are related to an increased risk of toxicity (10,27).…”

“…Trough concentrations of more than 2 mg/l are related to an increased risk of toxicity (10,27). High trough concentrations can, therefore, be correlated with early renal impairment before the potentially toxic effects of gentamicin development (27). (76).…”

Acute renal failure after high-dose antibiotic bone cement: case report and review of the literature

“…A significant concern associated with scenarios like this ALBC elution case is the persistent exposure to aminoglycoside levels 41.0 mcg/mL for an extended period since elevated troughs and plasma concentration-time area under the curve are considered risk factors for aminoglycoside-induced nephrotoxicity. [51][52][53][54][55] We postulate that this likely contributed to the prolonged AKI since the spacers were not removed until the subsequent amputation two months later. Hemodialysis was never initiated which would have assisted with systemic aminoglycoside removal when it was at its highest.…”