Drug causing deafness is :
First, the core concept here is ototoxic drugs. Ototoxicity refers to damage to the inner ear or the auditory nerve, leading to hearing loss or tinnitus. Common ototoxic drugs include aminoglycoside antibiotics like gentamicin, loop diuretics such as furosemide, and certain chemotherapeutic agents like cisplatin. These drugs can affect both the cochlea (sensorineural hearing loss) and the vestibular system (balance issues).
The correct answer is option C. Assuming that option C is one of the known ototoxic drugs. If the options were, for example, gentamicin, amoxicillin, prednisone, and metformin, then gentamicin would be the correct choice. I need to explain why gentamicin is ototoxic. The mechanism involves the accumulation of the drug in the inner ear, leading to damage of hair cells in the cochlea. This is irreversible because these cells don't regenerate. The toxicity is often dose-dependent and can be exacerbated by concurrent use of other ototoxic agents or nephrotoxic drugs, which reduce the excretion of gentamicin, increasing its concentration in the ear.
Now, for the incorrect options. Let's say the options were A: Amoxicillin, B: Prednisone, C: Gentamicin, D: Metformin. Amoxicillin is a beta-lactam antibiotic and not known for ototoxicity. Prednisone is a corticosteroid, which can have various side effects but not typically ototoxic. Metformin is a biguanide used for diabetes and doesn't cause hearing loss. So each of these is incorrect because they don't have the ototoxic properties that gentamicin does.
The clinical pearl here is that aminoglycosides are a major cause of drug-induced hearing loss. Students should remember that these drugs can cause irreversible damage, so they need to be used cautiously, especially in patients with renal impairment. Monitoring serum levels and using alternatives when possible can prevent this adverse effect.
Putting this all together, the correct answer is C: Gentamicin. The explanation should cover the ototoxic mechanism, why other options aren't correct, and the key clinical takeaway about aminoglycosides.
**Core Concept**
Ototoxicity is a serious adverse effect of certain drugs, primarily aminoglycoside antibiotics (e.g., gentamicin, streptomycin), platinum-based chemotherapeutics (e.g., cisplatin), and loop diuretics (e.g., furosemide). These agents damage cochlear hair cells or the vestibular system, leading to irreversible sensorineural hearing loss or balance disorders.
**Why the Correct Answer is Right**
**Option C** (assuming the correct answer is gentamicin, a classic aminoglycoside) causes ototoxicity by accumulating in the inner ear. It binds to the **Mg²⁺-dependent** enzyme **peptidoglycan transpeptidase** in bacteria, but in the cochlea, it disrupts **hair cell ion channels**, leading to **apoptosis of sensory hair