Which of the following aminoglycosides are the most nephrotoxic?

• A. Amikacin, Kanamycin, Neomycin
• B. Streptomycin, Gentamicin
• C. Gentamicin, Tobramycin, Neomycin
• D. Spectinomycin, Mupirocin

Answer: (C)

Nephrotoxicity from aminoglycosides happens when the drug accumulates in the renal proximal tubule cells, causing tubular injury. Among these antibiotics, gentamicin and tobramycin are classic for a higher risk of kidney toxicity with systemic use, especially with longer courses or higher trough levels. Neomycin is also highly nephrotoxic if it reaches the circulation, even though it’s not often given parenterally because of this toxicity. So, the combination of Gentamicin, Tobramycin, and Neomycin carries the greatest nephrotoxic potential.

By contrast, amikacin generally has a lower nephrotoxicity risk than gentamicin and tobramycin, and streptomycin is usually less nephrotoxic as well. Spectinomycin and mupirocin aren’t typical systemic nephrotoxic agents (mupirocin is mainly topical; spectinomycin has a different usage profile).