A wide variety of drugs can be ototoxic. Medication-related factors affecting ototoxicity include
Dose
Duration of therapy
Concurrent renal failure
Infusion rate
Lifetime dose
Coadministration with other medications that have ototoxic potential
Genetic susceptibility
Ototoxic medications should not be used for otic topical application when the tympanic membrane is perforated because the medications might diffuse into the inner ear.
Aminoglycosides, including the following, can affect hearing:
tends to cause more damage to the vestibular portion than to the auditory portion of the inner ear. Although vertigo and difficulty maintaining balance tend to be temporary, severe loss of vestibular sensitivity may persist, sometimes permanently. Loss of vestibular sensitivity causes difficulty walking, especially in the dark, and oscillopsia (a sensation that the environment is bouncing with each step). About 4 to 15% of patients who receive 1 g/day for > 1 week develop measurable hearing loss, which usually occurs after a short latent period (7 to 10 days) and slowly worsens if treatment is continued. Complete, permanent deafness may follow.
have vestibular and cochlear toxicity, causing impairment in balance and hearing.
can cause hearing loss, especially in patients with renal insufficiency.
Some mitochondrial DNA mutations predispose to aminoglycoside ototoxicity.
, a macrolide, causes reversible or irreversible hearing loss in rare cases.
Viomycin, a basic peptide with antituberculous properties, has cochlear and vestibular toxicity.
Chemotherapeutic (antineoplastic) medications,
given IV have caused profound, permanent hearing loss in patients with renal failure who had been receiving aminoglycoside antibiotics.
Salicylates in high doses (>
and its synthetic substitutes can cause temporary hearing loss.
(See also Hearing Loss.)
Prevention of Drug-Induced Ototoxicity
Ototoxic antibiotics should be avoided during pregnancy because they can damage the fetal labyrinth. Older adults and people with preexisting hearing loss should not be treated with ototoxic medications if other effective medications are available. The lowest effective dosage of ototoxic medications should be used and levels should be closely monitored, particularly for aminoglycosides (both peak and trough levels).
If possible before treatment with an ototoxic medication, hearing should be measured and then monitored during treatment; symptoms are not reliable warning signs.
Risk of ototoxicity increases with the use of multiple medications that have ototoxic potential and the use of ototoxic medications excreted through the kidneys in patients with renal compromise; in these cases, closer monitoring of medication levels is advised. In patients known to have mitochondrial DNA mutations that predispose to aminoglycoside toxicity, aminoglycosides should be avoided.
Key Points
Drugs may cause hearing loss, dysequilibrium, and/or tinnitus.
Common ototoxic medications include aminoglycosides, platinum-containing chemotherapy medications, and high-dose salicylates.
Symptoms may be transient or permanent.
Use the lowest possible dose of ototoxic medications and closely monitor levels of the medication (particularly aminoglycosides); measure medication levels during treatment to help prevent hearing loss caused by ototoxic medications.
Medications that cause or risk ototoxicity are stopped if possible, but there is no specific treatment.
