Renal toxicity during therapy with gentamicin or tobramycin

Area of Science:

• Nephrology
• Pharmacology
• Infectious Diseases

Background:

• Aminoglycosides like gentamicin and tobramycin are vital for treating bacterial infections.
• Assessing nephrotoxicity is critical for safe and effective aminoglycoside therapy.
• Baseline renal function is a key factor in predicting drug-induced kidney injury.

Purpose of the Study:

• To compare the effects of gentamicin versus tobramycin on renal clearance in patients with normal pretherapy kidney function.
• To evaluate potential biomarkers of aminoglycoside-induced nephrotoxicity.

Main Methods:

• Randomized trial involving 27 patients with normal renal clearance ([125I]iothalamate test).
• Patients received either gentamicin or tobramycin for susceptible bacterial infections.
• Renal clearance, serum creatinine, and urinary enzyme levels (N-acetyl glucosaminidase, alanine aminopeptidase) were monitored.

Main Results:

• A significant decrease in renal clearance (≥14%) was observed in 40% of gentamicin recipients and 58% of tobramycin recipients.
• Mean renal clearance decreased by 26% with gentamicin and 23% with tobramycin.
• Urinary enzyme levels increased more with gentamicin, but did not predict renal clearance decline.

Conclusions:

• Both gentamicin and tobramycin can reduce renal clearance in patients with initially normal kidney function.
• Serum creatinine increases were infrequent, highlighting the sensitivity of direct renal clearance measurements.
• Further research is needed to understand long-term renal effects and predictive biomarkers.