Ototoxicity refers to damage to the inner ear caused by certain drugs or chemicals. Common ototoxic drugs include aminoglycoside antibiotics, loop diuretics, cytotoxic agents, antiprotozoals, antiepileptics, and environmental chemicals. Symptoms of ototoxicity include hearing loss, tinnitus, and balance disorders and can be temporary or permanent depending on the offending agent. Diagnosis involves assessing a patient's exposure history and test results. While there are no treatments to reverse damage, management focuses on rehabilitation and avoiding further ototoxic exposure.

1. Ototoxicity

2. Overveiw
• Ototoxicity is, quite simply, ear
poisoning (oto = ear, toxicity =
poisoning), which results from exposure
to drugs or chemicals that damage the
inner ear or the vestibulo-cochlear nerve
(the nerve sending balance and hearing
information from the inner ear to the
brain).

3. What is ototoxicity
• Certain medications or drugs can damage the ear,
resulting in hearing loss, rigging in the ear (tinnitus) or
balance disorders. This disorders are considered
ototoxic.

4. Definition
• Ototoxicity is the damage caused by
the toxic effects of certain drugs to
either cochlear or vestibular or both
parts of the inner ear.
• Ototoxicity can be temporary or
permanent.

5. • The effect of certain drugs is often
temporary, while other drugs typically
produce permanent changes to the ear.
• Some drugs can cause either temporary or
permanent problems

6. Anatomical structure of inner ear

7. List of Ototoxic drugs
Aminoglycoside antibiotics
Loop diuretics
Cytotoxic agents ( Anti – neoplastic drugs )
Antiprotozoal
Antiepileptic drugs
Antiheparinzing agents
Beta blockers and Environmental chemicals

8. Aminoglycoside antibiotics
• All members of the aminoglycoside
antibiotic family are well known for their
potential to cause permanent ototoxicity if
they enter the inner ear.
• Some of these drugs are more likely to
cause hearing loss; others are more likely
to cause vestibular loss. Others can cause
either problem.

9. Aminoglycoside antibiotics
• Aminoglycoside antibiotics can enter
the inner ear through the blood system
or via diffusion from the middle ear
into the inner ear.
• They enter the blood stream in largest
amounts when given intravenously (by
IV) and in the least amounts by pill.

10. Examples for aminoglycoside
antibiotics
Amikacin
Netilmicin
Dihydrostreptomycin
Ribostamycin
Gentamicin
Streptomycin
Kanamycin t
Obramycin
Neomycin

11. Loop diuretics
• Loop diuretics are a specific family of
“water pills” that is known to
occasionally cause temporary
ototoxicity.
• These drugs cause ringing in the ears
or decreased hearing that reverses
when the drug is stopped.

12. Example for loop
diuretics
Bumetanide
(bumex)
Ethacrynic
acid
(edecrin)
Furosemide
(lasix)
Torsemide
(demadex)

13. Cytotoxic agents ( Anti – neoplastic drugs )
• Anti-cancer drugs work by killing cancer cells.
Unfortunately some can also damage or kill cells
elsewhere in the body, including the ears.
• Cisplatin is well known to cause massive and
permanent hearing loss. Carboplatin is also known
to be ototoxic
• For example 1. Nitrogen mustard
2. Cisplatinum
3. carboplatin

14. Antiprotozoal
• Aspirin and quinine Aspirin (acetylsalicylic acid, ASA)
and quinine are well known to cause temporary
ototoxicity resulting in tinnitus. They may also reduce
hearing, particularly when given at high doses. Quinine
products can also temporarily reduce balance ability.
Once aspirin or quinine is stopped, the ototoxicity
generally disappears.

15. Some quinine products include:
•Chloroquine
•Quinidine
•Quinine
(including q-vel)
• Tonic water

16. Antiepileptic drugs
• Phenytoin sodium

17. Beta - blockers
• Propranolol

18. Environmental chemicals
• Environmental chemicals have long
been implicated in ototoxicity. Little
research has been done to substantiate
their precise effect on ears, but most
are associated with hearing
disturbances that may be permanent.
In addition, mercury

19. Environmental agents
Butyl nitrite
Mercury
Carbon
disulphide
Styrene
carbon
monoxide
Tin
Lead
Manganese
xylene

20. Routes of access
• Ototoxic effects can be produced usually
by parenteral administration. Oral
administration or topical application to
ears, wounds, burns can also cause toxicity.

21. Clinical manifestations
• The signs & symptoms range from
mild tinnitus to total hearing loss,
depending upon each person and the
form and level of exposure to the
ototoxin.
• They can include one-sided or two-
sided hearing loss and constant or
fluctuating tinnitus.

22. Clinical manifestations
• High - pitched tinnitus is often the
earliest symptom.
• Sensorineural deafness
• Vertigo

23. Assessment and diagnosis
• The diagnosis is based upon the patient’s
history, symptoms, and test results.
• There is no specific test for ototoxicity;
this makes a positive history for ototoxin
exposure crucial to the diagnosis.

24. TREATMENT
• At present there are no treatments that can
reverse the damage. Currently available
treatments focus on reducing the effects of the
damage and rehabilitating function.
• Medical or surgical treatment is usually not
effective. Use of ototoxic drugs should be
avoided whenever possible.
• Specifically, individuals with hearing loss may
be helped with hearing aids; those with
profound bilateral (two-sided) hearing loss have
been shown to benefit from cochlear implants.

25. • Usual treatment given for sudden sensori- neural
deafness can be advised.
• Withdrawal of ototoxic drug may prevent further
damage in early cases.
• Hearing aids are advised in clients with established
deafness.
• Cochlear implants clients with profound bilateral
sensorineural deafness
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•

26. Hearing aids Cochlear implants

27. 1. Vestibular disorders association, Portland, By
P.J. Haybach, RN, MS.
2. A short textbook of E.N.T. Diseases K.B.
Bhargava, S.K Bhargava, T,M. Shah.