What can lead to toxic levels of gentamicin?

Gentamicin is an aminoglycoside antibiotic primarily eliminated from the body through the kidneys, so any factor that affects renal function or changes the pharmacokinetics of the drug can potentially lead to toxicity. The correct answer highlights the significance of serum albumin binding in the distribution and elimination of gentamicin.

In the context of toxic levels of gentamicin, when another medication binds to serum albumin, it can displace gentamicin from its binding site. This can increase the concentration of free (unbound) gentamicin in the bloodstream. Since gentamicin has a narrow therapeutic window, elevated free levels may lead to increased risk of nephrotoxicity and ototoxicity, as the drug can exert its adverse effects more significantly when unbound.

Other factors such as high-dose administration, use of medications affecting liver function, or dehydration affecting kidney function also contribute to the risk of toxicity. However, the specific pathway through albumin binding directly influences the effective concentration of gentamicin available in the serum, making this option particularly relevant to understanding the mechanics of gentamicin toxicity.