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. "Toxic" mean 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?

Approximately 200 drugs have been labeled as ototoxic. Different ototoxic drugs can cause either permanent or temporary structural damage in the inner ear. The damage can be of varying degree and reversibility.

Over the counter drugs know to cause hearing loss are:

• Asprin in large doses over a period of time.
• Quinine.

Drugs known to cause permanent damage are:

•  Aminoglycoside antibiotics 
• Cancer chemotherapeutic agents.
• Cisplatin.
• Carbo-platin.

Those known to cause temporary damage are:

• Salicylate analgesics.
• Loop diuretics. 

There are other categories of drugs known to be ototoxic including:

• Anesthetics.
• Cardiac medications
•  Glucocorticosteroids (cortisone, steroids).
• Mood altering drugs, 
• Some vapors and solvents.

In some instances, exposure to damaging noise while taking certain drugs will increase their ototoxicity.

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 if 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--9,000 to 20,000 Hz--because ototoxic drugs affect these frequencies first. This requires specialized testing equipment because the typical audiometer only test frequencies up to 8,000 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. In cases where hearing loss is inevitable and "planned for," the audiologist can plan and institute rehabilitation measures early.