Ototoxicity Monitoring Basics
Why some lifesaving treatments need a hearing “safety net” — and what to ask for.
If you notice a sudden big drop in hearing over hours–days (especially one-sided), new severe vertigo, or new neurologic symptoms (facial weakness, trouble speaking, confusion, double vision), seek urgent evaluation. Don’t wait for your next scheduled hearing test. Use /en/emergency.
Some of the most powerful tools in medicine—including certain chemotherapy drugs and strong IV antibiotics—come with a trade-off. They can be ototoxic, meaning they have the potential to damage the inner ear’s hearing and balance structures.
Ototoxicity monitoring is a proactive plan to check hearing (and sometimes balance) before, during, and after higher-risk treatments. The goal is to catch changes early so your care team can: (1) adjust what’s adjustable, and (2) support you quickly if changes are not avoidable.
Quick Start: 4 Things to Do
- Ask for a baseline hearing test before the first dose, or as close to the start as possible.
- Know your “trigger symptoms” (new tinnitus, muffled hearing, new imbalance) and who to message first.
- Ask what your program monitors (many use extended high frequencies and/or OAEs as early warning signs).
- Plan the follow-up after treatment ends (some effects can continue after the last dose).
Who Typically Needs Monitoring?
Not every medicine requires hearing testing. Monitoring is most often discussed when the benefit is huge and the ear risk is real, such as:
- Platinum-based chemotherapy (for example, cisplatin and sometimes carboplatin).
- Aminoglycoside antibiotics (for example, gentamicin, amikacin, tobramycin) used IV for serious infections.
- Loop diuretics (for example, high-dose IV furosemide), especially when combined with other ototoxic medicines.
- Cranial radiation (radiation involving the head/brain), which can have delayed effects on hearing.
Risk tends to increase with higher cumulative doses, kidney dysfunction, dehydration, noise exposure, pre-existing hearing loss, and combinations of multiple ototoxic medicines. Ask your team if any of these apply to you.
What Does “Baseline” Testing Include?
A baseline isn’t just “can you hear speech.” It’s a detailed snapshot that makes later changes easier to interpret. Many ototoxicity monitoring programs include:
- Case history (medicines, doses, symptoms, noise exposure, kidney issues, prior hearing loss).
- Otoscopy + tympanometry (to rule out middle-ear factors that can mimic a hearing change).
- Pure-tone audiometry (air & bone conduction), plus extended high frequencies when available.
- Speech testing (speech recognition thresholds and word recognition).
- DPOAEs (distortion product otoacoustic emissions) when appropriate — another way to look for early inner-ear change.
- ABR/ASSR (auditory brainstem response / auditory steady-state response) in select cases (for example, when behavioral testing is not feasible).
For several ototoxic exposures, early changes can show up at very high pitches before speech is clearly affected. Tracking those frequencies can give you and your clinicians an earlier warning signal.
How Often Are Re-Checks Done?
There is no single schedule that fits every hospital, medication, and patient. But for some well-studied exposures, professional guidance suggests patterns like these:
Platinum chemotherapy (cisplatin / carboplatin)
- Baseline before the first dose when possible.
- Monitoring during treatment: often before each cisplatin dose/cycle; for carboplatin, some programs monitor less frequently (for example, every 2–4 cycles), depending on regimen and risk.
- Follow-up: commonly at 3, 6, 9, and 12 months, then annually.
Cranial radiation (head/brain radiation)
- Baseline when feasible (often before treatment begins).
- Follow-up: some guidance suggests periodic checks for several years, with higher-risk situations monitored more frequently than lower-risk situations.
Monitoring schedules vary widely for infections and other conditions. A practical approach is to ask: “When do you want my baseline, how often do you re-check during treatment, and what symptoms should trigger an earlier test?” If your course is long or high-dose, it’s reasonable to ask whether periodic monitoring is available.
What Counts as a Meaningful Change?
Audiology teams use rules to separate “normal test variability” from a probable treatment effect. One commonly cited set of criteria (from ASHA-referenced grading/monitoring frameworks) flags possible ototoxic change if:
- ≥ 20 dB threshold worsening at any single test frequency, or
- ≥ 10 dB worsening at two adjacent frequencies, or
- worsening to “no response” at three consecutive test frequencies where responses were previously present.
Clinicians typically confirm with a repeat test (and consider middle-ear status, fatigue, equipment differences, etc.) before acting on a single data point.
A new “ringing,” “buzzing,” or “hissing” can be an early clue that the ear is irritated. If tinnitus starts or worsens during treatment, tell your team promptly and ask whether earlier monitoring is appropriate.
Balance Side Effects: Don’t Ignore Them
Some medicines can affect balance organs as well as hearing. Report new dizziness, unsteadiness, falls, or a “bouncy/blurred world when walking”. If severe or sudden—especially with neurologic symptoms—treat it as urgent and use /en/emergency.
What the UCSF EARS Navigator Can—and Can’t—Do
Your Ototoxicity Monitoring Navigator is designed to help patients and families organize questions and expectations. It’s most helpful when it does three things:
- Clarifies “bare minimum” building blocks (baseline → monitoring during treatment → follow-up after treatment).
- Provides sample wording for messages and clinic conversations.
- Routes to safety when symptoms sound urgent.
What it does not provide (important):
- It does not diagnose ototoxicity or determine the cause of a hearing change (fluid, infection, sudden sensorineural loss, wax, etc.).
- It does not know your regimen (dose, infusion timing, kidney labs, combination therapies) and can’t personalize risk.
- It does not replace local protocols (each center’s monitoring resources and thresholds for action differ).
- It cannot tell you to stop or change medication. Only your treating team can weigh that risk-benefit tradeoff safely.
How to Advocate (Copy/Paste Scripts)
Before treatment starts
- Message: “I’m starting a treatment that may affect hearing. Can we add a baseline hearing test before my first dose, or as close to the start as possible?”
- Ask: “If I notice new tinnitus, muffled hearing, or dizziness, who should I contact first and how quickly?”
During treatment
- Message: “I’m on treatment that can affect hearing. I’m noticing new [tinnitus / muffled hearing / imbalance]. Should I be checked earlier than the routine schedule?”
- Ask: “Do you monitor extended high frequencies and/or OAEs as early warning signs?”
After treatment ends
- Message: “My treatment ended recently. Can we schedule a follow-up hearing test to confirm my hearing has stabilized and to plan support if needed?”
Why It Matters
If changes are caught early, your team may be able to:
- Adjust dosage or infusion timing when clinically appropriate.
- Switch to an alternative if a safe substitute exists.
- Start hearing support early (hearing aids, assistive devices, communication strategies) to reduce fatigue and isolation.
Protecting your hearing is part of protecting your quality of life. A baseline plus a realistic monitoring plan helps your clinicians balance lifesaving treatment with communication and independence.
Next Steps: Build Your Hearing “Safety Net”
Use the Navigator to organize questions and create a simple plan you can share with your clinicians. For urgent symptoms, use the safety guide.
Further Reading
References
- ASHA Ototoxicity Monitoring (flowchart)
- Merck Manual: Drug-Induced Ototoxicity
- NIDCD: Sudden Deafness
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