Most people know that loud music, machinery and repeated noise exposure can damage their hearing. Far fewer realise that certain medications can do the same thing.
Some antibiotics, chemotherapy drugs, diuretics and even commonly used painkillers can affect the delicate structures of the inner ear. This is known as ototoxicity, and its effects can range from temporary tinnitus to permanent hearing loss or significant balance problems.
Ototoxicity is particularly concerning because the damage isn’t always immediately noticeable. It may begin at frequencies above the range of a conventional hearing test. In other cases, it affects balance rather than hearing, making the underlying cause surprisingly difficult to recognise.
The distinction matters because many ototoxic medications are used to treat serious, sometimes life-threatening conditions. The objective isn’t necessarily to avoid these medicines. It’s to understand their risks, identify people who are more susceptible and monitor hearing and balance where appropriate.
What Is Ototoxicity?
Ototoxicity is damage to the hearing or balance system caused by exposure to certain medications or chemicals.
The term comes from oto, meaning ear, and toxicity, meaning the harmful effects of a substance.
There are two main forms:
- Cochleotoxicity: Damage to the cochlea, the hearing organ within the inner ear. This can cause hearing loss, tinnitus and difficulties understanding speech.
- Vestibulotoxicity: Damage to the vestibular organs responsible for balance and detecting head movement. This can cause unsteadiness, impaired balance and difficulty keeping vision stable while moving.
Some substances affect both systems. Others have a greater tendency to damage one than the other.
This distinction is particularly important because someone can experience significant vestibular damage while having relatively normal hearing.
A 2021 scientific review by Peter Steyger, published in the American Journal of Audiology, describes the mechanisms through which medications such as aminoglycoside antibiotics and cisplatin chemotherapy damage the inner ear.
Importantly, ototoxicity is not the same as age-related hearing loss or noise-induced hearing loss, although these conditions can coexist and may make the effects of ototoxicity more significant.
How Does Ototoxicity Damage the Inner Ear?
To understand why certain medications damage hearing, it helps to understand how the cochlea works.
Inside the cochlea are thousands of specialised sensory cells known as hair cells.
These cells detect mechanical vibrations produced by sound and help convert them into electrical signals that travel through the auditory nerve to the brain.
The cochlea also contains supporting structures, including the stria vascularis, which maintains the specialised chemical environment needed for hearing.
Ototoxic substances can interfere with these processes in several ways.
1. Oxidative stress and cellular damage
Certain medications increase the production of reactive oxygen species within inner-ear tissues.
These highly reactive molecules are part of normal cellular processes, but when produced in excessive quantities they can damage proteins, membranes and DNA.
This process is known as oxidative stress.
Both cisplatin and aminoglycoside antibiotics can trigger molecular pathways involving oxidative stress, mitochondrial dysfunction and ultimately cell death.
2. Direct damage to sensory hair cells
Some ototoxic medications accumulate inside cochlear hair cells.
Aminoglycosides, for example, can enter these cells through specialised ion channels involved in detecting sound vibrations.
Once inside, they can disrupt cellular function and trigger processes that kill the cells.
The problem is that, unlike birds and some other animals, humans cannot naturally regenerate lost cochlear hair cells.
When these cells are permanently destroyed, the resulting sensorineural hearing loss is generally irreversible.
3. Disruption of the cochlea’s electrical environment
Not all ototoxicity involves directly destroying hair cells.
Some medications affect the stria vascularis, which maintains the electrical potential necessary for normal hearing.
Loop diuretics, including furosemide, can temporarily disrupt this system.
The resulting hearing changes may recover when the medication’s effects subside, although permanent damage is possible in certain circumstances.
4. Damage to the vestibular system
Other medications can damage the sensory structures that detect head movement and help stabilise vision.
This can interfere with the vestibulo-ocular reflex, which normally keeps your eyes focused on an object while your head moves.
Damage to this system can make the visual world appear to bounce or blur while walking.
This symptom is called oscillopsia.
The mechanisms involved are described in the open-access review Aminoglycoside- and Cisplatin-Induced Ototoxicity: Mechanisms and Otoprotective Strategies.
Which Medications Can Cause Ototoxicity?
A wide range of medications have been investigated for possible ototoxic effects, but the evidence varies considerably.
Some are well-established causes of permanent inner-ear damage. Others are associated primarily with temporary changes, particular doses or relatively uncommon adverse reactions.
| Medication class | Examples | Potential effects |
|---|---|---|
| Platinum-based chemotherapy | Cisplatin, carboplatin | Permanent sensorineural hearing loss, tinnitus |
| Aminoglycoside antibiotics | Gentamicin, amikacin, tobramycin, streptomycin | Hearing loss, balance damage |
| Loop diuretics | Furosemide, bumetanide, ethacrynic acid | Usually temporary hearing changes; sometimes permanent |
| Salicylates | High-dose aspirin | Tinnitus and usually reversible hearing loss |
| Other anti-inflammatory medicines | Ibuprofen, naproxen | Possible hearing effects, particularly with high or repeated exposure |
| Macrolide antibiotics | Erythromycin, azithromycin, clarithromycin | Uncommon hearing changes; evidence varies |
| Antimalarial medications | Quinine, chloroquine | Tinnitus, hearing loss and sometimes vestibular symptoms |
| Some other medications | Hydroxychloroquine, vancomycin | Reported or possible effects; evidence is less certain and context-dependent |
Being listed here does not mean a medication will cause hearing loss or that it should be avoided. The strength of evidence, dose, treatment duration, underlying medical conditions and other medications all affect the risk.
Let’s look at the main causes in more detail.
1. Chemotherapy and Ototoxicity: Why Cisplatin Can Damage Hearing
Cisplatin is one of the best-established causes of medication-related hearing loss.
It is a highly effective chemotherapy medicine used in the treatment of several cancers, including testicular, ovarian, bladder, lung and head and neck cancers.
Unfortunately, its ability to damage rapidly dividing cancer cells is accompanied by toxic effects on other tissues, including the inner ear.
How common is cisplatin-induced hearing loss?
Research has reported permanent hearing loss in approximately 40–80% of some cisplatin-treated populations.
That is a broad range, and it should not be interpreted as the individual risk for everyone receiving cisplatin.
The likelihood and severity depend on factors including cumulative chemotherapy dose, age, other treatments, existing hearing function and the criteria used to define hearing loss.
Cisplatin-related hearing loss is typically bilateral, meaning that both ears are affected, and often begins at higher frequencies.
The earliest changes may occur above 8,000 Hz, beyond the upper limit of many conventional hearing assessments.
As the damage progresses, lower frequencies essential for understanding speech may become affected.
People may initially notice that voices sound less clear, particularly in background noise, even when speech still seems sufficiently loud.
Why can hearing deteriorate after chemotherapy has finished?
One of the most interesting discoveries in ototoxicity research concerns how long platinum can remain in the cochlea.
A 2017 study published in Nature Communications, Cisplatin Is Retained in the Cochlea Indefinitely Following Chemotherapy, investigated platinum accumulation in human and animal inner-ear tissue.
The researchers found that, unlike many other organs that eliminate cisplatin over days or weeks, the cochlea can retain platinum for considerably longer.
In human tissue, platinum was detectable at least 18 months after chemotherapy.
The researchers also identified particularly high concentrations within the stria vascularis.
These findings help explain why cisplatin-related hearing damage can have long-term effects and why ongoing monitoring may be appropriate after treatment.
What about carboplatin?
Carboplatin is another platinum-based chemotherapy medicine.
It is generally considered less ototoxic than cisplatin at conventional doses, but hearing damage can still occur, particularly with high-dose treatment or other risk factors.
Patients receiving either medicine should discuss the need for hearing monitoring with their oncology team.
Australian cancer treatment guidance from eviQ recommends monitoring auditory function before, during and after potentially ototoxic treatment.
2. Antibiotics and Ototoxicity: Gentamicin, Amikacin and Tobramycin
Antibiotics are another important cause of ototoxicity, particularly a class known as aminoglycosides.
These medications remain essential for treating some serious bacterial infections.
Examples include:
- Gentamicin
- Tobramycin
- Amikacin
- Streptomycin
- Neomycin
- Kanamycin
Aminoglycosides can be particularly effective against certain bacteria, but they can also damage the inner ear and kidneys.
The likelihood of toxicity generally increases with greater cumulative exposure, prolonged treatment, impaired kidney function and certain genetic characteristics.
Repeated treatment courses may also increase risk.
Gentamicin is particularly associated with balance damage
One of the more surprising aspects of aminoglycoside ototoxicity is that gentamicin can damage balance without producing an obvious hearing problem.
This isn’t a theoretical concern.
In 2012, Australian researchers published Gentamicin Ototoxicity: A 23-Year Selected Case Series of 103 Patients in the Medical Journal of Australia.
The researchers reviewed 103 patients who had developed severe bilateral vestibular dysfunction following gentamicin treatment.
Patients commonly experienced persistent imbalance, difficulty walking and oscillopsia.
Yet only three reported some hearing impairment, and their audiometric thresholds were consistent with their age.
The study also identified an important problem: vestibular toxicity had occurred in some patients despite gentamicin blood concentrations being within recommended ranges.
This was a selected group of patients referred for severe vestibular problems, so the findings cannot be used to estimate how frequently gentamicin causes these effects in all patients.
Nevertheless, the study illustrates why hearing tests alone are insufficient to exclude vestibular ototoxicity.
A person who develops persistent unsteadiness after gentamicin treatment may require specialist vestibular assessment even when their hearing appears normal.
Can a single dose cause ototoxicity?
It is possible, although uncommon.
Individual susceptibility varies, and certain genetic variants can substantially increase the risk of aminoglycoside-related hearing loss.
This means that a medication considered reasonably safe for most patients may carry a much greater risk for someone with a particular genetic predisposition.
3. Genetic Susceptibility: Why Some People Are More Vulnerable
Ototoxicity is not determined by medication dose alone.
Genetics can play a significant role.
One of the best-studied examples involves variants in a mitochondrial gene called MT-RNR1.
Mitochondria are structures within cells responsible for producing much of the energy needed for cellular activity.
Certain MT-RNR1 variants make the mitochondrial protein-production machinery particularly susceptible to aminoglycoside antibiotics.
The result can be significant hearing damage at doses that would not ordinarily produce the same effect in other patients.
Important variants include m.1555A>G and m.1494C>T.
In 2022, the Clinical Pharmacogenetics Implementation Consortium published guidelines recommending that aminoglycosides generally be avoided in people with recognised high-risk MT-RNR1 variants unless the severity of the infection and absence of effective alternatives justify the risk.
These variants are inherited through mitochondrial DNA, which is generally passed down through the maternal line.
A family history of hearing loss associated with antibiotics may therefore be particularly relevant.
If someone has a known MT-RNR1 variant, or a family history suggestive of aminoglycoside-related deafness, they should tell their treating doctor before receiving these medications.
4. Can Antibiotic Ear Drops Cause Hearing Loss?
Yes, under certain circumstances.
This is particularly relevant to people with a perforated eardrum, a functioning grommet or an open middle-ear cavity following surgery.
When the eardrum is intact, it normally separates the external ear canal from the middle ear.
However, when there is an opening, some medications placed into the ear canal may enter the middle ear and potentially reach the inner ear.
Aminoglycoside-containing ear drops, including preparations containing neomycin, framycetin or gentamicin, can pose an ototoxicity risk in these circumstances.
The Australian Society of Otolaryngology Head and Neck Surgery has published recommendations favouring non-ototoxic ear drops when the eardrum is perforated or grommets are present.
The actual risk depends on the preparation, the condition of the ear, the duration of treatment and other factors.
Not all antibiotic ear drops are ototoxic, and sometimes a specialist may judge that a potentially ototoxic medicine is necessary.
If you have a perforated eardrum or grommets, make sure your doctor or pharmacist knows before using ear drops.
Research and Australian clinical guidance: Ototoxic Ear Drops with Grommet and Tympanic Membrane Perforations: A Position Statement.
5. Diuretics: Can Furosemide Cause Ototoxicity?
Furosemide, also called frusemide, is a commonly used loop diuretic.
It helps the body remove excess fluid and is prescribed for conditions such as heart failure, fluid retention and some forms of kidney disease.
Although furosemide is not usually associated with hearing problems when taken at appropriate routine doses, it can cause ototoxicity under certain circumstances.
Risk is greater with high doses, particularly rapid intravenous administration, impaired kidney function or concurrent use of other ototoxic medications.
Unlike cisplatin-related hearing loss, furosemide-related changes are often reversible.
The mechanism is also different.
Furosemide can interfere with the stria vascularis, disrupting the electrical potential required for normal cochlear function.
An important concern is that loop diuretics can increase the ototoxic effects of some other medications, particularly aminoglycoside antibiotics.
A scientific review published in the Journal of Otology describes these mechanisms in detail.
Research:Ototoxic Effects and Mechanisms of Loop Diuretics.
6. Can Aspirin, Ibuprofen and Other Painkillers Damage Hearing?
This is an area where it’s particularly important to distinguish established effects from associations that are still being investigated.
Aspirin
High doses of aspirin can cause tinnitus and temporary hearing loss.
These effects have been recognised for decades and are associated with salicylate exposure.
The hearing changes are often reversible after the dose is reduced or the medicine is discontinued under medical supervision.
However, this should not be confused with the much lower doses of aspirin commonly prescribed to reduce cardiovascular risk.
Clinically significant ototoxicity is uncommon at those low doses.
Ibuprofen and other NSAIDs
Non-steroidal anti-inflammatory drugs (NSAIDs), including ibuprofen and naproxen, have also been associated with hearing changes.
High doses can produce ototoxic effects, although the evidence varies between individual medications.
Researchers have also investigated whether long-term, regular use of common analgesics is associated with hearing loss.
A prospective study involving 26,917 men found associations between regular use of aspirin, NSAIDs or paracetamol and an increased likelihood of reported hearing loss.
However, observational associations do not establish that these medications directly caused the hearing loss.
Other factors, including underlying illness, noise exposure and patterns of medication use, may contribute.
It would therefore be misleading to suggest that taking an occasional recommended dose of ibuprofen or paracetamol is likely to damage your hearing.
The more relevant questions concern dose, frequency, duration and individual risk factors.
Research:Analgesic Use and the Risk of Hearing Loss in Men.
7. Macrolide Antibiotics: Azithromycin, Clarithromycin and Erythromycin
Macrolide antibiotics are used to treat a range of bacterial infections.
Examples include azithromycin, clarithromycin and erythromycin.
Hearing loss associated with these medications has been reported, but the evidence is less straightforward than it is for aminoglycosides.
A 2024 systematic review and meta-analysis published in Scientific Reports examined 13 studies involving more than 1.1 million participants.
The researchers found a modest association between macrolide exposure and hearing loss, with a pooled odds ratio of 1.25.
However, there was substantial variation between the studies, and not all study designs demonstrated a statistically significant association.
This means the findings warrant attention, but they don’t establish that macrolides commonly cause permanent hearing damage.
If you notice hearing changes or tinnitus while taking a macrolide, discuss them promptly with your prescribing doctor rather than assuming the medication is responsible or stopping treatment without advice.
Research:Increased Risk of Hearing Loss Associated with Macrolide Use: A Systematic Review and Meta-analysis.
8. Antimalarial Medications: Quinine and Hydroxychloroquine
Quinine has a well-established history of affecting hearing.
It can produce tinnitus, reduced hearing sensitivity and other symptoms sometimes grouped under the term cinchonism.
Hearing changes associated with therapeutic quinine exposure are often temporary, although more serious or persistent effects have been reported, particularly with excessive exposure.
Other antimalarial medicines, including chloroquine and hydroxychloroquine, have also been investigated for possible auditory and vestibular toxicity.
However, the strength of evidence differs between medications.
For hydroxychloroquine, published reports suggest that ototoxicity can occur, but the overall frequency, mechanisms and extent of permanent risk remain uncertain.
This is important because hydroxychloroquine is used to treat conditions such as lupus and rheumatoid arthritis, where the underlying disease itself may also be associated with hearing problems.
A 2021 systematic review concluded that more high-quality human research was needed to establish the extent and permanence of hearing damage associated with antimalarial medicines.
Research:Ototoxic Hearing Loss from Antimalarials: A Systematic Narrative Review.
9. Industrial Chemicals, Solvents and Heavy Metals
Ototoxicity isn’t limited to prescribed medication.
Certain industrial and environmental chemicals can also affect hearing.
Research has identified potentially ototoxic substances including:
- Organic solvents such as toluene, styrene and xylene
- Lead and some mercury compounds
- Carbon monoxide
- Certain pesticides and industrial chemicals
These exposures may occur in manufacturing, construction, painting, industrial cleaning and other workplaces.
The effects depend on the substance, concentration, duration and route of exposure.
The combined effect of chemicals and noise
An important concern is that chemical exposure and noise exposure may interact.
Traditionally, occupational hearing conservation has focused heavily on decibel levels and the amount of time employees spend in noisy environments.
However, research suggests that exposure to certain solvents can increase hearing risk, particularly when combined with occupational noise.
A systematic review and meta-analysis published in 2017 found an increased risk of hearing loss among workers exposed to mixtures of organic solvents, with a greater risk when solvent exposure occurred alongside noise.
The evidence does not imply that every exposure to paint or cleaning products will damage hearing. Industrial exposure levels, protective equipment and working conditions matter considerably.
Nevertheless, workplace hearing conservation should consider relevant chemical exposures as well as noise.
Research:The Risk of Hearing Loss Associated with Occupational Exposure to Organic Solvents.
The US National Institute for Occupational Safety and Health also provides guidance on chemical-induced hearing loss.
10. Radiotherapy and Treatment-Related Hearing Loss
Although radiotherapy isn’t a medication or chemical exposure, it is another medical treatment that can damage hearing structures.
Radiation involving the head or neck may affect the inner ear, auditory nerve or middle-ear structures, depending on the area treated and the radiation dose.
Risk may increase when radiotherapy is combined with ototoxic chemotherapy.
This is particularly important for children and young people, where hearing loss can interfere with speech, language development, learning and social interaction.
International guidelines recommend hearing surveillance for certain childhood cancer survivors who have received platinum chemotherapy, head or brain radiotherapy, or both.
What Are the Symptoms of Ototoxicity?
Ototoxicity does not always cause immediately recognisable hearing loss.
The symptoms depend on which structures are affected and how the damage develops.
Common warning signs include:
Tinnitus: Ringing, buzzing, whistling or other sounds heard without an external sound source.
Difficulty hearing high-pitched sounds: Reduced perception of softer consonants, alarms or other high-frequency sounds.
Difficulty understanding speech: Particularly in restaurants, group conversations and other environments with background noise.
Muffled hearing: Voices or environmental sounds may seem less clear than usual.
Unsteadiness: Difficulty walking confidently, particularly in the dark or on uneven surfaces.
Oscillopsia: The impression that objects bounce or blur when walking or moving your head.
Dizziness or vertigo: Some vestibular problems cause spinning sensations, although bilateral vestibular loss can produce imbalance without obvious spinning vertigo.
Why might you not notice the damage immediately?
The earliest effects of cochlear ototoxicity often involve high frequencies.
If hearing changes initially occur above 8,000 Hz, a person may still hear ordinary conversations reasonably well.
Likewise, bilateral vestibular damage can develop gradually and may be mistaken for general weakness, ageing or recovery from an illness.
This is why monitoring should not depend entirely on patients noticing symptoms.
Who Is Most at Risk of Ototoxicity?
Not everyone receiv
