Ototoxicity and nephrotoxicity is caused by:
**Core Concept**
The question tests the student's knowledge of the adverse effects of certain medications, specifically their potential to cause ototoxicity (damage to the ear) and nephrotoxicity (damage to the kidneys). These effects are primarily mediated by the inhibition of renal and auditory function due to the accumulation of toxic metabolites.
**Why the Correct Answer is Right**
The correct answer involves the inhibition of an enzyme that is crucial for the detoxification of aminoglycoside antibiotics. Aminoglycosides, such as gentamicin and tobramycin, are commonly used to treat severe bacterial infections. However, their use is associated with a risk of ototoxicity and nephrotoxicity. The mechanism underlying these adverse effects is the inhibition of the enzyme 16S ribosomal subunit by aminoglycosides, which disrupts protein synthesis in the kidneys and inner ear. This results in the accumulation of toxic metabolites that cause tissue damage.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it does not accurately describe the mechanism of ototoxicity and nephrotoxicity. Aminoglycosides are not primarily metabolized by the liver, and their toxicity is not due to their effects on the liver.
* **Option B:** This option is incorrect because it does not accurately describe the mechanism of ototoxicity and nephrotoxicity. Cephalosporins are a class of beta-lactam antibiotics that are not associated with ototoxicity and nephrotoxicity to the same extent as aminoglycosides.
* **Option C:** This option is incorrect because it does not accurately describe the mechanism of ototoxicity and nephrotoxicity. Fluoroquinolones are a class of antibiotics that are associated with toxicity to the tendons and cartilage, but not primarily with ototoxicity and nephrotoxicity.
**Clinical Pearl / High-Yield Fact**
Aminoglycosides should be used with caution in patients with pre-existing kidney disease or hearing impairment, and their use should be monitored closely with regular assessments of renal function and hearing.
**Correct Answer: A. Aminoglycosides**