After antibiotic treatment for pneumonia, which drug is most likely responsible for increased serum creatinine?

The correct answer is tobramycin, as it is an aminoglycoside antibiotic known for its potential nephrotoxic effects. Aminoglycosides, including tobramycin, can cause increased serum creatinine levels due to their effects on the kidneys. They are often associated with acute kidney injury, particularly in patients with pre-existing kidney issues or those receiving other nephrotoxic drugs.

Tobramycin works by inhibiting bacterial protein synthesis, which is effective in treating serious infections, but its nephrotoxicity necessitates careful monitoring of renal function. In particular, the accumulation of tobramycin in the renal cortex can lead to tubular cell damage, resulting in elevated creatinine levels.

Other antibiotics listed, such as doxycycline, clarithromycin, and linezolid, generally have a much lower risk of causing renal impairment compared to tobramycin. Doxycycline is a tetracycline antibiotic effective against a range of bacteria but lacks significant nephrotoxicity. Clarithromycin, a macrolide, primarily has gastrointestinal side effects and linezolid, while it can cause some hematological effects, does not typically lead to increased serum creatinine in the way aminoglycosides do. Therefore,