2. InTRODUCTION
A variety of medication have adverse effects on the
cochlea, vestibular apparatus, or cranial nerve 8.The
effects of ototoxicity can be reversible and temporary
or irreversible and permanent.The effects of certain
drugs is temporary,while other drugs typically
produce permanent changes to the ear.
3. 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.
4. INCIDENCE
The cisplatin ototoxicity occurs between 23%
and 50% in adults and up to 60% in children
.However, some studies have reported elevated
hearing thresholds in up to 100% of cisplatin-
treated cancer patients while it is estimated to
be 63% with aminoglycosides and 6-7% with
furosemide .
5. High risk groups
Patients having impaired rental function.
Elderly patients age above 64 years.
Patients simultaneously receiving other ototoxic drugs.
Patients who have genetic susceptibility to these group of
drugs.
Patients under prolonged treatment.
7. Aminoglycoside Antibiotics
All members of 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.
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 steam in larger amount when given IV and in
the least amount by pill.
Eg: Amikacin, Neomycin, Obramycin,steptomycin etc.
8. 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 deceased hearing
that reverses when the drug is stopped.
Mostly reversible but permanent damage may occur.
Eg: Bumetanide ( bumex)
Ethacrynic acid (edecrin)
Furosemide ( lasix)
Torsemide ( demadex)
9. Antimalarials
Ototoxic effect is due to vasoconstriction in the small vessels
of the cochlea and stria vascularis.
The effect is reversible which generally appears on prolonged
medication, but deafness is permanent with chloroquine.
Congenital deafness and hypoplasia of cochlea have been
reported in children whose mother’s received these drugs
during pregnancy (first trimester).
Eg: Quinine and chloroquine
10. Anticancer drugs
Nitrogen
Mustards ( cyclophosphamide ,Ifosfamide),Cisplastin,Carboplatin
can cause cochlear damage.
Ototoxic effect is due to outer hair cell degeneration leading
to high frequency sensory neural hearing loss.
11. Analgesics
Ototoxic effect is reversible and is due to interference at
enzymatic level.
No structural damage hence normal histology( no hair cell
loss )
Symptoms: Tinnitus and hearing loss
NSAIDS like salicylates ,Indomethacin,Phenyl
butazone,ibuprofen.
12. 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.
13.
14. CLINICAL MANIFESTATION
High pitched tinnitus is often the earliest symptom
Sensorineural deafness
Vertigo
Mild tinnitus to total hearing loss depending upon
each person and form and level of exposure to the
ototoxin.
They can include one sided or two sided hearing loss
and constant or fluctuating tennitus.
15. 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.
History collection
Physical examination
Electrocochleography
Eexamination
Electrocochleography
Electronystagmography
Auditory brainstem response
16. TREATMENT
At present their are no treatments that can reverse
the damage. Currently available treatments focus on
reducing the effect of the damage and rehabilitating
function.
Medical or surgical treatment is usually not effective.
Use of ototoxic drugs should be avoided whenever
possible.
Those with profound bilateral ( two- sided) hearing
loss have been shown benifit from Cochlear implants.
17. 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.
Tinnitus treated by mild hypnotics.
18.
19. NURSING MANAGEMENT
Assess the level of antibiotics to ensure adequate
treatment and to prevent ototoxicity.
Teach the patient about the complications of
priscribed drugs.
20. HEALTH TEACHING
Advice the patient to avoid toxic drugs .
Advice patient to avoid intake of drugs without priscription.
Ask patient to avoid toxic drugs if they are taking any other
toxic drugs.
Advice patient to avoid contact with environmental chemicals.
Teach patient about importence of taking medicinemediciness
according to the prescription.
22. CONCLUSION
Various drugs can result in hearing loss ,which may or
may not be reversible.Certain mechanisms are
responsible for the hearing loss ,which can either be
cochleo or vestibulotoxic.So prevent the chance for
toxic effect because ototoxic damage is often times
irreversible.
