Medication Effects on Hearing

Commonly used medications--both over-the-counter and prescribed--can damage hearing or aggravate an already existing problem.

Any drug with the potential to cause toxic reactions to structures of the inner ear are considered ototoxic ("oto-" means ear and "toxic" means poisonous: therefore, ototoxic means poisonous to the ear).

Hearing problems caused by ototoxic medications are often reversible if the drug is discontinued. Sometimes, however, hearing loss is permanent. When a decision is made to treat an illness or medical condition with a drug known to be ototoxic, the health care team should consider the effects that hearing and balance problems may have on the person's quality of life after the drug therapy.

If a drug is known to cause permanent hearing loss or even deafness, why is it used ?

Sometimes there is little choice. A particular drug may be the only known medication available to cure a life-threatening disease or to stop a life-threatening infection.

What drugs are ototoxic?

Over 130 drugs and chemicals are reported to be potentially ototoxic ^1,2 . Different ototoxic drugs can cause either permanent or temporary structural damage in the inner ear. The damage can be of varying degree and reversibility.

Those drugs known to cause permanent damage are the aminoglycoside antibiotics and the cancer chemotherapeutic agents cisplatin and carboplatin.

Those known to cause temporary damage are salicylate analgesics, quinine, and loop diuretics. In some instances, exposure to damaging noise while taking certain drugs will increase their ototoxicity.

There are other categories of drugs known to be ototoxic including anesthetics, cardiac medications, glucocorticosteroids (cortisone, steroids), mood-altering drugs, and some vapors and solvents.

It is important to discuss the potential for ototoxicity of any drug you are taking with your physician and/or pharmacist.

Can the use of a known ototoxic drug be monitored to determine whether hearing loss is occurring?

Yes, audiologists can perform hearing tests before, during, and after the administration of medications to detect the progression of ototoxic hearing loss. This evaluation usually involves testing hearing in very high frequency ranges--9000 to 20000 Hz--because ototoxic drugs affect these frequencies first. (Typical hearing tests only test frequencies as high as 6000 or 8000 Hz.)

Hearing tests are done before the administration of the drug to obtain baseline information. Monitoring is done at scheduled intervals to detect threshold changes as early as possible. Data gathered through monitoring helps the physician to make a decision to stop or change the drug therapy before hearing in the frequencies critical for speech is damaged. For cases in which hearing loss is inevitable and "planned for," the audiologist can plan and institute rehabilitation measures.

Monitoring of hearing usually continues as part of rehabilitation to determine whether the hearing loss is stable. Rehabilitation may include fitting hearing aids, assistive listening devices, and communication management.

References

1. García, V.P., Martínez, F.Z., Agusti, E.B., Mencía, L.A., & Asenjo, V.P. (2001). Drug-induced ototoxicity: Current status. Acta Oto-laryngologica, 121, 569-572.
2. Seligmann, H., Podoshin, L., Ben-David, J., Fradis, M. & Goldsher, M. (1996). Drug-induced tinnitus and other disorders. Drug Safety, 14, 198-212.