Most people think of hearing loss as something that creeps up with age, or happens because you spent too many years at loud concerts without earplugs. What fewer people realise is that some of the medications sitting in their bathroom cabinet can damage their hearing. Sometimes temporarily. Sometimes for good.
The clinical term is ototoxicity. “Oto” meaning ear, “toxic” meaning exactly what you think. It refers to drugs or chemicals that poison the structures of the inner ear, particularly the delicate hair cells in the cochlea that convert sound vibrations into electrical signals your brain can interpret. Once those hair cells die, they don’t grow back. Not in humans. Not yet, anyway.
Which Medications Can Damage Your Hearing?
The list is longer than most people expect. A major analysis of the World Health Organisation’s global adverse drug reaction database identified over 325,000 reports of ototoxic reactions across a surprisingly wide range of drug classes (Bosetti et al., 2019). We’re not talking about obscure experimental treatments. Many of these are medications prescribed every day in Australia.
Aminoglycoside Antibiotics
These are the textbook ototoxins. Gentamicin, tobramycin, amikacin, streptomycin. They’re powerful antibiotics used for serious infections, particularly in hospital settings, and they’ve been known to damage hearing since the 1940s.
The numbers vary wildly depending on the study. Reported incidence of hearing loss from aminoglycosides ranges from near zero to 63%, which tells you how much dosage, duration, and individual susceptibility matter (Contartese et al., 2023). Recent prospective data from patients receiving streptomycin found a 74% probability of hearing loss by the end of treatment, with average onset at around 28 weeks (Adeyemo et al., 2024).
The damage typically starts in the high frequencies and works its way down. Outer hair cells in the base of the cochlea go first. By the time you notice trouble following conversations, the loss has usually been progressing for a while.
What makes aminoglycoside ototoxicity particularly tricky is the genetic component. Certain mitochondrial DNA mutations, especially m.1555A>G, can make a person extraordinarily sensitive. One dose can be enough. In carriers of this mutation, exposure can cause hearing loss with up to 100% penetrance (Gaafar et al., 2024). Genetic screening before aminoglycoside treatment is gaining traction, but it’s far from routine in most Australian hospitals.
Platinum-Based Chemotherapy
Cisplatin is one of the most effective cancer-fighting drugs ever developed. It’s also one of the most reliably ototoxic. More than 60% of children treated with cisplatin develop permanent hearing loss, typically high-frequency sensorineural loss that starts during treatment and can worsen even after it stops.
The drug enters hair cells through multiple transport channels, binds to DNA, triggers a cascade of oxidative stress, and overwhelms the cell’s ability to repair itself. The outer hair cells in the base of the cochlea take the worst hit because of their higher metabolic demands. A 2020 mouse study demonstrated that cisplatin accumulates significantly in cochlear tissue, while the related drug carboplatin is largely excluded from the cochlea at equivalent doses.
Carboplatin is less ototoxic than cisplatin, but “less” doesn’t mean “safe.” At high cumulative doses (above 1,500 mg/m²), carboplatin causes notable hearing damage too. A 2012 study of sarcoma patients found similar ototoxicity rates of around 46% for both drugs, though cisplatin achieved this at much lower cumulative doses.
For anyone undergoing platinum-based chemotherapy, baseline hearing tests before treatment and regular monitoring throughout are essential. Catching changes early gives oncologists the option to adjust treatment before the damage becomes severe.
Other Common Ototoxic Medications
The list extends well beyond antibiotics and chemotherapy drugs:
Loop diuretics like furosemide (Lasix) can cause hearing loss, usually temporary, but potentially permanent at high doses or when combined with other ototoxic drugs. They’re prescribed for heart failure, kidney disease, and high blood pressure. Millions of Australians take them.
Aspirin and salicylates at high doses can cause tinnitus and temporary hearing loss. The classic sign is ringing in the ears after taking too much aspirin. It usually reverses when you stop or reduce the dose, but not always.
Quinine and antimalarials like chloroquine have documented ototoxic effects, relevant for travellers and people being treated for malaria or certain autoimmune conditions.
Some antidepressants and cardiovascular drugs showed up as disproportionate signals in the WHO pharmacovigilance database. So did tramadol, which many people wouldn’t think of as a hearing risk.
Tacrolimus, an immunosuppressant used after organ transplants, has also been flagged.
The 2024 review by Reynard and colleagues notes that even some illicit drugs carry ototoxic risk, a detail that rarely makes it into public health messaging.
Workplace Chemicals That Damage Hearing
Ototoxicity isn’t just a pharmaceutical problem. Industrial chemicals can damage hearing too, and the risk gets worse when chemical exposure combines with noise.
Solvents are the main culprits. Toluene, styrene, xylene, trichloroethylene. These are found in paints, adhesives, degreasers, and manufacturing processes. Workers in printing, painting, fibreglass production, and automotive industries face the highest exposure levels.
Asphyxiants like carbon monoxide and hydrogen cyanide also damage the cochlea, targeting the stria vascularis (the structure that maintains the chemical environment the hair cells need to function) and triggering excitotoxic damage to auditory nerve fibres (Campo et al.).
WorkSafe guidelines acknowledge over 750 groups of potentially ototoxic chemicals, but only a fraction have been studied in any detail. The research that does exist paints a clear picture: chemical exposure and noise together do more damage than either one alone. This has real implications for workplace hearing conservation programs. Monitoring noise levels without considering chemical exposure misses half the equation.
For employers running workplace hearing assessments, understanding ototoxic chemical exposure is part of meeting Clause 58 compliance obligations properly. Testing protocols should account for what workers are breathing in, not just what they’re hearing.
How Ototoxic Damage Actually Happens
The details get complicated fast, but the broad strokes are worth understanding because they explain why this kind of hearing loss is so hard to reverse.
Most ototoxic drugs and chemicals converge on the same basic pathway. They generate reactive oxygen species (free radicals) inside hair cells. These overwhelm the cell’s antioxidant defences, damage mitochondria (the cell’s power generators), disrupt calcium regulation, and trigger programmed cell death.
With aminoglycosides, the drug enters hair cells through the same channels that normally let in potassium and calcium. Once inside, it wrecks the mitochondria and generates a flood of free radicals. Genetic variations in mitochondrial DNA explain why some people lose their hearing after a single course of antibiotics while others tolerate months of treatment.
With cisplatin, the drug binds directly to DNA and also fires up a specific enzyme called NOX3 that exists almost exclusively in the cochlea. This creates a feedback loop: oxidative stress opens more channels, letting in more cisplatin, generating more oxidative stress. The damage peaks between 90 and 210 minutes after exposure and cascades from there.
With solvents, the mechanisms are less well mapped but appear to involve direct damage to the stria vascularis and excitotoxic overstimulation of the auditory nerve through glutamate flooding.
In every case, the outer hair cells go first. These are the amplifiers of the cochlea, responsible for boosting quiet sounds and sharpening frequency discrimination. Losing them makes speech harder to pick apart, especially in noisy environments. That’s why people with ototoxic hearing loss often say they can hear that someone’s talking but can’t make out the words. And what is truly amazing, is that we have one specific test that can directly measure outer hair cell function directly – the Otoacoustic Emission.
Who’s Most at Risk?
Several factors stack the odds against you:
Age matters. Older adults are more vulnerable, and so are very young children whose auditory systems are still developing. The predictive model from a 2024 aminoglycoside study found that each year of age increases ototoxic risk by about 5%.
Dose and duration. Higher cumulative doses mean more damage. Each additional gram of streptomycin raised ototoxic risk by 7% in the same study.
Kidney function. Most ototoxic drugs are cleared through the kidneys. Impaired kidney function means higher blood levels for longer, which means more exposure for the cochlea.
Combining ototoxic agents. Taking an aminoglycoside while also receiving cisplatin, or using loop diuretics alongside either, multiplies the risk. Drug interactions in ototoxicity are not just additive. They can be synergistic.
Genetics. The mitochondrial mutations mentioned earlier (particularly m.1555A>G) create extreme vulnerability to aminoglycosides. Family history of drug-induced hearing loss is a red flag worth mentioning to any prescribing doctor.
Pre-existing hearing loss. If your hearing is already compromised, you have less margin before ototoxic damage becomes functionally significant.
Noise exposure. Occupational noise combined with ototoxic chemical exposure accelerates hearing damage beyond what either factor would cause independently.
What Can You Do About It?
Awareness is the starting point. If you’re prescribed any of the medications mentioned above, ask your doctor about hearing monitoring. This isn’t about scaring you off necessary treatment. Aminoglycosides save lives. Cisplatin cures cancers. But knowing the risk means you and your medical team can watch for early signs and adjust if needed.
Before treatment: Get a baseline hearing test. Full audiometry including high frequencies and really importantly Otoacoustic Emissions (OAEs). These tests give everyone both a subjective and an objective a reference point. If hearing shifts during treatment, you’ll know by how much and how fast.
During treatment: Regular monitoring, especially extended high-frequency audiometry and OAEs, catch changes before they reach the speech frequencies that affect daily communication. The earlier a shift is detected, the more options exist for modifying treatment.
After treatment: Hearing loss from ototoxic drugs can progress even after you stop taking them, particularly with platinum agents. Follow-up testing matters.
In the workplace: If you’re exposed to solvents or other ototoxic chemicals on the job, make sure your employer’s hearing conservation program accounts for chemical exposure, not just noise levels. And if you’re wearing hearing protection for noise, remember it does nothing to protect against chemicals entering through the lungs and bloodstream.
Research into otoprotective agents, drugs that might shield hair cells during ototoxic treatment, is active but still largely experimental. Antioxidants like D-methionine and N-acetylcysteine have shown promise in animal studies, but human clinical trials have produced mixed results so far (2024 antioxidant review). For now, monitoring and early detection remain the most reliable strategies.
How The Audiology Place Can Help
At The Audiology Place, we offer the kind of detailed diagnostic testing that ototoxicity monitoring requires. That includes extended high-frequency audiometry (testing above the standard 8 kHz range where ototoxic damage typically shows up first), otoacoustic emissions testing, and full speech-in-noise assessment.
As an independent clinic, we work with your treating specialists directly. No manufacturer affiliations influencing recommendations. No agenda beyond getting you the most accurate picture of your hearing health and the best advice on protecting it.
If you’re about to start treatment with a potentially ototoxic medication, or you work in an environment with chemical exposure, a baseline hearing assessment is one of the smartest things you can do. It takes about an hour. It could save you years of preventable hearing loss.
Book a hearing assessment or call us on 9315 8327 to discuss your situation.
Frequently Asked Questions
What does ototoxic mean?
Ototoxic means toxic to the ear. It describes any substance, whether a medication, industrial chemical, or environmental agent, that can damage the structures of the inner ear responsible for hearing and balance. The damage most commonly affects the hair cells in the cochlea, which are essential for converting sound into nerve signals.
What are the most common ototoxic medications?
The most well-documented ototoxic medications include aminoglycoside antibiotics (gentamicin, tobramycin, streptomycin), platinum-based chemotherapy drugs (cisplatin, carboplatin), loop diuretics (furosemide), high-dose aspirin and salicylates, quinine, and some antimalarials. The WHO adverse drug reaction database also flags certain antidepressants, cardiovascular drugs, tramadol, and the immunosuppressant tacrolimus.
Can ototoxic hearing loss be reversed?
It depends on the drug and the extent of damage. Hearing loss from high-dose aspirin or loop diuretics is often temporary and reverses when the medication is stopped or reduced. Hearing loss from aminoglycosides and cisplatin is usually permanent because these drugs destroy cochlear hair cells, which do not regenerate in humans. Early detection through monitoring gives the best chance of limiting the damage.
Should I get a hearing test before starting chemotherapy?
Yes. Baseline audiometry before chemotherapy, particularly platinum-based regimens, is strongly recommended. This provides a reference point so any hearing changes during treatment can be detected early. Extended high-frequency testing is especially valuable because ototoxic damage typically affects higher frequencies before it reaches the speech range.
Can workplace chemicals cause hearing loss?
Yes. Organic solvents like toluene, styrene, and xylene are documented ototoxins found in many industrial settings. Carbon monoxide and hydrogen cyanide also damage hearing. The risk is significantly higher when chemical exposure occurs alongside occupational noise, as the two interact to cause more damage than either would alone.
How do I know if my medication is affecting my hearing?
Watch for tinnitus (ringing, buzzing, or hissing in the ears), a sense of fullness in the ears, difficulty understanding speech especially in background noise, or sounds seeming muffled or distorted. These symptoms may develop gradually. If you’re on a known ototoxic medication and notice any changes in your hearing, contact your prescriber and arrange a hearing assessment promptly.
Does genetic testing help predict ototoxic risk?
For aminoglycoside antibiotics, yes. Mitochondrial DNA mutations, particularly m.1555A>G, dramatically increase susceptibility. Carriers can develop severe hearing loss from a single dose. Genetic screening before aminoglycoside treatment is increasingly recommended, though it’s not yet routine practice in most Australian hospitals. If you have a family history of drug-induced hearing loss, mention it to your doctor before starting any ototoxic medication.
References:
- Bosetti C et al. (2019). Ototoxic Adverse Drug Reactions: A Disproportionality Analysis Using the WHO Global Database.
- Contartese G et al. (2023). Aminoglycosides-Related Ototoxicity: Mechanisms, Risk Factors.
- Adeyemo AA et al. (2024). Re-telling the Story of Aminoglycoside Ototoxicity.
- Gaafar AH et al. (2024). Pharmacogenetics of Aminoglycoside-Related Ototoxicity.
- Reynard P et al. (2024). Drug-induced Hearing Loss: Listening to the Latest Advances.
- Pasdelou MP et al. (2024). Ototoxicity: A High Risk to Auditory Function That Needs to Be Monitored in Drug Development.
- Campo P et al. Chemical Exposure and Hearing Loss.
- Wu et al. (2024). Multiple Mechanisms of Aminoglycoside Ototoxicity.
Disclaimer: This article is for informational purposes only and does not replace professional medical advice, diagnosis, or treatment. Do not stop or change any medication without consulting your prescribing doctor. Always seek the advice of your physician, audiologist, or other qualified health provider with questions regarding a medical condition or treatment.
