Ototoxicity: How Medication and Other Chemicals May Affect Your Hearing

by Thomas A. Powers, PhD

Ototoxicity is the process of a medication or other drug causing damage to your hearing, specifically the hearing nerve or the vestibular (balance) system.  Ototoxicity typically results when the inner ear is poisoned by medication that damages the cochlea, vestibule, semi-circular canals, or the auditory/vestibulocochlear nerve. The exact mechanism that causes this damage is not fully understood, however, the effect has been recognized since the 1800s. This damage can be reversible and temporary, or irreversible and permanent. Many well-known ototoxic drugs are prescribed in critical health situations, such as kidney failure, despite the risk of hearing loss. 

Ototoxic drugs include the following: antibiotics such a gentamicin, streptomycin, tobramycin, loop diuretics such as furosemide and platinum-based chemotherapy agents such as cisplatin and carboplatin.  Some nonsteroidal anti-inflammatory drugs (NSAIDS) have also been shown to be ototoxic.

Additionally, some environmental and occupational chemicals have been shown to affect the auditory system and may be exacerbated when combined with noise exposure.

Ototoxic effects are also seen with quinine, pesticides, solvents, asphyxiants and heavy metals such as mercury and lead. The results of exposure to these can be sensorineural hearing loss, balance issues, or both.

Symptoms of an ototoxic reaction may be:

• Ringing or buzzing sounds in ears (tinnitus)
• Dizziness/loss of balance
• Change in hearing, which may occur in both ears, or start in one ear and progress to the other ear
• Hearing loss usually happens first in the extremely high pitches (frequencies) that are above the range of speech, but if undetected this can progress to affect the speech frequencies.
• When balance is affected, you may fall frequently and have symptoms of disequilibrium — an unsteady “woozy” feeling that makes it hard to stand up, walk, or climb the stairs without falling.

If you are prescribed any of the classes of drugs mentioned above, your physician may request your hearing to be monitored by an audiologist throughout your treatment. If possible, have your hearing tested prior to taking an ototoxic medication. This test then can be used to compare future tests to determine if any change has occurred to your hearing.  In addition, you may have daily or regular hearing testing to monitor any decrease in your hearing abilities while taking the medication. Testing of the balance system (vestibular testing) may also be used to assess possible effects on balance. 

As these types of drugs or medications are used in critical health situations, their use is balanced between the treatment of the underlying disease and the damage to your hearing.

If permanent hearing damage is detected, treatment options include hearing aids, hearing assistive technology and cochlear implants to improve communication. To find an audiologist near you to ask questions or have your hearing tested, please visit https://betterhearing.org/find-a-hearing-health-care-professional/