Increased trough levels of aminoglycosides are often associated with toxic effects to which organ?

• A. Heart
• B. Kidney
• C. Pancreas
• D. Liver

Answer: (B)

Aminoglycosides are cleared by the kidneys, and their toxicity is closely tied to the drug exposure the kidneys experience between doses. The trough level—the lowest concentration just before the next dose—reflects how much drug remains in the bloodstream and, by extension, how much accumulates in renal tubular cells. When trough levels are elevated, the kidneys are exposed for a longer period at higher concentrations, increasing the risk of nephrotoxicity (acute kidney injury) due to damage to proximal tubular cells. This is why trough monitoring is crucial: it helps limit renal injury by guiding dose adjustments.

The heart, pancreas, and liver are not the typical targets of toxicity driven by trough-level exposure to aminoglycosides. Ototoxicity can occur with these drugs, but it is more linked to peak exposure and cumulative dose rather than elevated troughs.