Ototoxic drugs: which ones, who is at risk and how to monitor

Topic

Some medicines damage the inner ear; aminoglycosides and cisplatin do so permanently, so hearing is monitored during treatment.

Updated Nov 5, 2026

Key points

Aminoglycosides: auditory and vestibular ototoxicity, usually irreversible; risk rises with renal impairment, high doses or long courses, advanced age and dehydration.
The mitochondrial variant m.1555A>G (maternal inheritance) predisposes to aminoglycoside deafness even with serum levels in range.
Cisplatin: cumulative damage that starts in the high frequencies (4000 to 8000 Hz) with tinnitus; children under 5 are at higher risk.
Loop diuretic plus aminoglycoside (or cisplatin) adds ototoxicity; rapid injection and severe renal impairment raise the risk with furosemide.
Quinine and salicylates: tinnitus and hearing loss; with quinine the picture (cinchonism) usually reverses when the drug is stopped.
Monitoring: a baseline audiogram and serial audiograms that include the high frequencies, plus asking about tinnitus, vertigo and hearing loss at every review.

What it is

Ototoxicity is damage to the cochlea, the vestibular system or both caused by a medicine. The WHO names ototoxic medicines as a preventable cause of hearing loss in adults and recommends their rational use and hearing screening for people who receive them. The two groups exams ask about most are aminoglycosides (usually irreversible auditory and vestibular damage) and cisplatin (cumulative high-frequency damage, very common in children). Loop diuretics, salicylates, quinine and macrolides complete the classic list.

Key facts

The gentamicin label lists dizziness, vertigo, tinnitus, roaring in the ears or hearing loss as warning signs: they require dose adjustment or stopping the drug.
With a maternal history of aminoglycoside ototoxicity or a known mitochondrial variant, alternatives are considered unless the severity of the infection justifies the risk.
Cisplatin ototoxicity shows as tinnitus and high-frequency hearing loss; it is estimated to affect 40 to 60 % of treated children.
Genetic variants (for example in the TPMT gene) may contribute to cisplatin ototoxicity.
Furosemide can cause tinnitus and reversible or irreversible hearing impairment, and has been associated with hearing loss in neonates.
Azithromycin has postmarketing reports of hearing loss, deafness and tinnitus.
In the newborn, exposure to aminoglycosides and maternal exposure to ototoxic drugs are risk factors for hearing screening.

Step by step

Before starting, ask about previous hearing loss, a maternal family history of aminoglycoside deafness, and check renal function.
Order a baseline audiogram when the course is long or high risk (aminoglycosides, cisplatin).
Avoid combining ototoxic drugs (aminoglycoside with a loop diuretic) and adjust the drug to renal function.
At every review ask about tinnitus, ear fullness, hearing loss, dizziness or unsteadiness.
Repeat the audiogram during treatment, including the high frequencies, and compare it with the baseline.
If it changes, discuss stopping or switching the drug with the treating team and refer to audiology.
After treatment, keep following the hearing of children treated with cisplatin: the loss is cumulative.

Classic ototoxic drugs

Group	What it damages	Key fact	How the risk is reduced
Aminoglycosides (gentamicin, amikacin, streptomycin)	Cochlea and vestibule	Usually irreversible; mitochondrial variant m.1555A>G	Monitor renal and eighth-nerve function, serum levels, serial audiograms; avoid potent diuretics
Cisplatin	Cochlea, high frequencies first	Cumulative and may be severe; more common in children	Audiometry and vestibular function in all patients, especially children
Loop diuretics (furosemide, ethacrynic acid)	Cochlea	Reversible or irreversible; potentiate aminoglycosides and cisplatin	Avoid rapid injection and combinations; caution in severe renal impairment
Salicylates (acetylsalicylic acid)	Cochlea	Ringing in the ears or hearing loss means stop and seek advice	Ask about tinnitus during long courses
Quinine	Cochlea	Cinchonism: tinnitus, hearing loss and, if severe, deafness; usually reverses	Stop if cinchonism appears and assess hearing
Macrolides (azithromycin)	Cochlea	Reports of hearing loss, deafness and tinnitus	Monitor hearing in long or combined courses

In clinical practice

Cisplatin hearing loss starts in the high frequencies (4000 to 8000 Hz): monitoring audiometry must include them.
Aminoglycosides also damage the vestibule: dizziness, vertigo or unsteadiness during treatment are signs of toxicity.
In patients with renal impairment the risk of ototoxicity from aminoglycosides and furosemide is higher.
Sudden, unilateral or asymmetric hearing loss during treatment should not simply be blamed on the drug: it needs the sudden hearing loss approach.

Next step / Initial management

Initial workup: pure-tone audiometry including high frequencies, renal function and aminoglycoside serum levels where relevant.
Management: stop or switch the ototoxic drug with the treating team, correct dehydration and avoid other ototoxic or nephrotoxic drugs at the same time.
Same-day referral to ENT if the loss is sudden, unilateral or asymmetric.
Urgent referral (within days) to audiology and ENT if hearing loss, tinnitus or vertigo appears during treatment.
Routine referral to hearing rehabilitation (hearing aids, implant) if permanent hearing loss remains.

Test yourself

Think of the answer, then tap the question to see it.

A 30-year-old woman becomes deaf after a short course of gentamicin with normal levels; her mother had the same. What explains this?

A maternally inherited mitochondrial DNA variant (m.1555A>G) that predisposes to aminoglycoside ototoxicity even with serum levels in range.

A 4-year-old receives cisplatin for a solid tumour. What hearing loss pattern is expected and how is it monitored?

Bilateral, cumulative sensorineural hearing loss starting in the high frequencies, with tinnitus. It is monitored with audiometry and vestibular function during and after treatment.

Which drug combination clearly raises the risk of ototoxicity in a patient with sepsis and renal impairment?

An aminoglycoside together with a potent loop diuretic such as furosemide or ethacrynic acid; renal impairment adds risk to both.

A patient on quinine reports tinnitus, headache, nausea and blurred vision. What is this picture called and how does it usually evolve?

Cinchonism. Most symptoms, including tinnitus and mild hearing loss, reverse when quinine is stopped; severe forms can cause deafness.

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Educational content; it does not replace a medical assessment and is not a clinical instruction. For a real case, follow current guidelines and specialist advice.

Sources: Deafness and hearing loss (fact sheet) (World Health Organization, 2026); Gentamicin injection: prescribing information (boxed warning and warnings) (U.S. National Library of Medicine, DailyMed, 2023); Cisplatin injection: prescribing information (ototoxicity, pediatric use) (U.S. National Library of Medicine, DailyMed, 2023); Furosemide injection: prescribing information (ototoxicity) (U.S. National Library of Medicine, DailyMed, 2023); Quinine sulfate capsule: prescribing information (cinchonism) (U.S. National Library of Medicine, DailyMed, 2023); Azithromycin tablets: prescribing information (postmarketing adverse reactions) (U.S. National Library of Medicine, DailyMed, 2025); Aspirin tablet: drug facts (stop use warnings) (U.S. National Library of Medicine, DailyMed, 2017).

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