3. Fate:

Metabolism of the aminoglycosides does not occur in the host. All are rapidly excreted into the urine, predominantly by glomerular filtration Accumulation occurs with renal failure and requires dose modification. Excretion of aminoglycosides is directly proportional to creatinine clearance. With normal renal function, the elimination half-life of aminoglycosides is 2–3h.Monitoring of plasma levels of aminoglycosides is important for safe and effective dosage selection and adjustment. For traditional dosing regimens (2 or 3 times daily), peak serum levels are measured 30–60 min after administration and trough levels just before the next dose. With once-daily dosing, peak levels are less important since they will naturally be high.