Chemotherapy is a definite source of ototoxicity. Ototoxicity is, quite simply, ear poisoning (oto = ear, toxicity = poisoning), which results from exposure to drugs or chemicals that damage the inner ear or the vestibulo-cochlear nerve (the nerve sending balance and hearing information from the inner ear to the brain). Because the inner ear is involved in both hearing and balance, ototoxicity can result in disturbances of either or both of these senses. The parts of the brain that receive hearing and balance information from the inner ear can also be affected by poison, but this is not technically considered ototoxicity and won’t be covered in this information sheet. (Poisoning of the brain is classified as neurotoxicity)
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The occurrence and degree of inner ear poisoning depends upon the drug involved as well as other factors such as heredity. Ototoxicity can be temporary or permanent. The effect of certain drugs is often temporary, while other drugs typically produce permanent changes to the ear. Some drugs can cause either temporary or permanent problems. It is important to note here that the broad majority of people who experience ototoxicity have a temporary or reversible form that does not result in a major or long-term disruption in their lives.
No one knows how many people suffer from ototoxicity each year or the percentage of vestibular disorders caused by ototoxicity. What is known is that when permanent and extensive ototoxicity occurs, the effects can take a terrible toll on a person’s ability to function
Scientific studies are required to confirm whether a drug is ototoxic. Unfortunately, such research often involves years of study. When assessing the safety of a drug prior to releasing it on the market, the U.S. Food and Drug Administration does not require testing of inner ear function or examination of the inner ear structures. This is one reason it is almost impossible to say with confidence how many and which drugs cause ototoxicity and how many or which people are affected by it.
Certain medications can damage the ear, resulting in hearing loss, ringing in the ear, or balance disorders. These drugs are considered ototoxic. There are more than 200 known ototoxic medications (prescription and over-the-counter) on the market today. These include medicines used to treat serious infections, cancer, and heart disease.
Ototoxic medications known to cause permanent damage include certain aminoglycoside antibiotics, such as gentamicin (family history may increase susceptibility), and cancer chemotherapy drugs, such as cisplatin and carboplatin.
Drugs known to cause temporary damage include salicylate pain relievers (aspirin, used for pain relief and to treat heart conditions), quinine (to treat malaria), and loop diuretics (to treat certain heart and kidney conditions).