Usually, these are relatively mild. Or, at the very least, they're less severe than the condition a drug is meant to treat. 

However, in some cases, one's reaction to a drug may cause temporary (or even permanent) damage to part of the body. Ototoxic medications, for instance, affect the ears and may cause tinnitus, balance problems, and hearing loss, known collectively as ototoxicity.

What Are Some Examples of Ototoxic Drugs?

Per the American Speech-Language-Hearing Association, there are approximately 200 known ototoxic medications. Another estimate places the number at closer to 600. Specifics aside, it's important to understand that some drugs are more frequently ototoxic than others.

Moreover, taking an ototoxic medication does not guarantee that you'll experience ototoxicity, something we'll discuss more in a moment. Your doctor is obligated to inform you of the potential side effects of any drug they prescribe, including ototoxicity. Drugs commonly understood to be ototoxic include: 

  • Some brands of antibiotics
  • Chemotherapy drugs,
  • Aspirin
  • Quinine
  • Loop diuretics

What are the Risk Factors for Ototoxicity?

Although 200-600 may seem like a significant number at first, consider that in the United States alone, there are over 20,000 approved prescription drugs. As such, it's fair to say that ototoxicity is a relatively uncommon side effect. Unfortunately, that means that the precise mechanism by which an ototoxic drug damages the ear isn't fully understood. We do not know for sure what causes one person to experience ototoxicity while another remains unaffected. 

What we do know is that certain environmental and genetic factors may increase the risk of ototoxicity: 

  • Exposure to loud noise while using medication
  • Age
  • Genetic history
  • Dosage level and rate
  • Use of multiple ototoxic drugs
  • Issues with kidney function
  • Previous exposure to ototoxic medication or radiation therapy
  • The presence of pre-existing hearing impairment

What Are The Warning Signs of Ototoxicity?

The symptoms of ototoxicity are relatively similar to other types of hearing loss. The first thing you'll likely notice is a persistent phantom noise in the ear — tinnitus, in other words. Although high-pitched ringing is one of the more common presentations of tinnitus, you may also notice clicking, roaring, or buzzing. 

This may not manifest immediately and may only become noticeable as you continue to use an ototoxic medication. Over time, you may also begin to feel unsteady on your feet. Ototoxic hearing loss may occur suddenly or gradually enough so that it may not even be noticeable until it begins to impact your ability to understand speech. 

Other symptoms may include: 

  • Dizziness
  • Hyperacusis
  • A feeling of fullness in the ears
  • Vision impairment
  • Loss of coordination

How is Ototoxicity Detected?

There are currently no tests to detect ototoxicity. Instead, hearing impairment stemming from an ototoxic drug may be detected in the same fashion as other forms of hearing loss. With that in mind, we strongly recommend visiting your audiologist for a hearing test prior to starting treatment with an ototoxic medication. 

This will allow your audiologist to establish a baseline hearing level, which can then be used to detect the early warning signs of an ototoxic reaction. 

What Can Be Done to Treat Ototoxicity?

We recommend immediately speaking to your doctor if you notice any symptoms of ototoxicity, as long-term use of ototoxic medication can cause permanent damage. Fortunately, if you catch the side effects early enough, treatment is usually as simple as stopping treatment of the drug. Do not do this without approval from your doctor. 

It's also important to note that in some cases, you may have no choice but to continue using the medication—because, in the long term, hearing loss is far less severe than the condition you're taking the medication for. 

Beyond that, ototoxicity may be managed in the same manner as other hearing and balance issues. Potential treatments may include physiotherapy to restore balance, speech therapy to assist with hearing impairment, or the prescription of hearing aids. In extreme cases, a patient suffering from ototoxicity may even consider cochlear implants or a similar surgery.