Hearing Health Guide
Definition
Ototoxic medications are pharmaceutical agents that can cause damage to the inner ear, specifically the cochlea (hearing) and the vestibular apparatus (balance). The damage may be dose-dependent or idiosyncratic, temporary or permanent. The primary target is the cochlear hair cells, whose loss is irreversible in humans. Ototoxicity monitoring (serial audiological testing before, during, and after treatment) is standard of care for high-risk agents.
Aminoglycoside antibiotics (gentamicin, tobramycin, streptomycin, amikacin): used for serious gram-negative bacterial infections. Cochlear and vestibular damage is cumulative. Genetic susceptibility variants (MT-RNR1 mutation) dramatically increase individual risk. IV administration carries far greater risk than topical ear drops with an intact eardrum.
Platinum-based chemotherapy (cisplatin, carboplatin): cisplatin produces permanent high-frequency sensorineural hearing loss in a substantial proportion of patients, particularly children. Carboplatin is less ototoxic. Loop diuretics (furosemide, ethacrynic acid): generally reversible at standard doses; risk increases significantly when combined with aminoglycosides. High-dose aspirin (above 3g/day): causes reversible tinnitus and hearing changes. Quinine and some antimalarials: reversible tinnitus and occasional hearing changes at therapeutic doses.
New tinnitus, particularly high-pitched bilateral tinnitus, is often the first sign of cochlear ototoxicity. This may be followed by perceived hearing difficulty, particularly for high-frequency sounds. Vestibular ototoxicity presents as oscillopsia (world bouncing with each step), unsteadiness, or chronic imbalance, often without vertigo.
Because high-frequency loss begins above the range of conversational speech, significant cochlear damage can occur before the person notices functional difficulty. Extended high-frequency audiometry (above 8,000 Hz) detects changes earlier than conventional testing.
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