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Ototoxicity and your Hearing Health

Prepared in observance of observance of OSHA Safe and Sound Week, 2021

 

What is ototoxicity

Ototoxicity is hearing impairment caused by exposure to ototoxins - medications and chemicals that can be inhaled, absorbed through the skin, or consumed.

 

The condition is worsened when the exposure is combined with other risk factors for hearing impairment such as hazardous noise, certain underlying health conditions, certain lifestyle habits, genetic factors.

What are known ototoxins?

1. Drugs

Several categories of drugs that are used commonly including some that have been recently approved by health authorities have varying levels of ototoxicity. The table below summarizes drugs (generic names) and the medical condition for which they are commonly prescribed or available over-the-counter. There are several hundred brand names associated with these drugs.

 

Acetazolamide - Edema

Acetaminophen - Pain, fever

Alendronic acid - Osteoporosis

Amikacin - Bacterial infections

Amphotericin B - Fungal infections

Artemether - Malaria

Aspirin - Pain, fever

Avanafil - Erectile dysfunction

Azithromycin - Mycobacterial infections

Bismuth subsalicylate - Diarrhea

Boceprevir - Hepatitis C

Bortezomib - Cancer

Bromocriptine - Acromegaly, Parkinson’s

Bumetanide - Edema

Carboplatin - Cancer

Celecoxib - Pain

Chlormethine - Cancer

Cisplatin - Cancer

Clonazepam - Seizure, panic

Cyclosporine - Organ transplantation

Docetaxel - Cancer

Deferasirox - Iron overload

Deferiprone - Iron overload

Deferoxamine - Iron overload

Ethacrynic acid - Edema

Enalapril - High blood pressure

Erythromycin - Bacterial infection

Febuxostat - Gout

Fenoprofen - Arthritis, Pain

Flumazenil - Drowsiness

Furosemide - Edema

Gabapentin - Neuralgia

Gentamicin - Bacterial infection

Hydroxychloroquine - Malaria

Ibuprofen - Pain

Interferon alpha - Hepatitis C

Isotretinoin - Acne

Itraconazole - Fungal infection 

Kanamycin - Bacterial infection

Leuprolide - Cancer

Meropenem - Bacterial infection

Mefloquine - Malaria

Naproxen - Arthritis

Neomycin - Bacterial infection

Nicotine - Smoking cessation

Nilotinib - Cancer

Ofloxacin - Ear infection

Plazomicin - Urinary tract infection

Pramipexole - Parkinson’s disease

Quinine - Malaria

Ribavirin/Intron A - Hepatitis C

Rivastigmine - Dementia

Ropinirole - Parkinson’s disease

Ropivacaine - Anesthesia

Sildenafil - Erectile dysfunction

Sodium valproate - Epilepsy  

Streptomycin - Bacterial infection

Sumatriptan - Migraine

Tacrolimus - Transplant

Tadalafil - Erectile dysfunction

Teprotumumab - Thyroid eye disease

Terbinafine - Fungal infection

Thalidomide - Cancer

Tobramycin - Bacterial infection

Topiramate - Seizure

Vancomycin - Bacterial infection

Valproic acid - Seizure

Vardenafil - Erectile dysfunction

Verteporfin - Eye disorder

Vinblastine - Cancer

Vincristine - Cancer

Vinorelbine - Cancer

Viomycin - Tuberculosis

Zoledronic acid - Osteoporosis

Chemicals

2. Chemicals

Can be used as part of occupational or personal activities.

Acrylonitrile

Arsenic

3-Butenenitrile

Carbon Disulfide

Carbon Monoxide

Chemical Warfare Agents

Cis-2-pentenenitrile

Cis-crotononitrile

Cyanide

Diesel fuel

Ethylbenzene

Fuels

Germanium dioxide

Heptane

Hydrogen cyanide

3,3’-iminodipropionitrile

Jet fuel

JP-8 fuel

Kerosene fuel

Manganese

Mercury

Methyl Ethyl Ketone

Methylstyrene

N-Hexane

N-propylbenzene

 Nitriles

Organic lead

Organic tin

Pesticides

P-xylene

Paraquat

Perchloroethylene

Polychlorinated biphenyls

Stoddard Solvent

Styrene

Tobacco smoke

Toluene

Trichloroethylene

Xylene         

 

These chemicals are used in construction, firefighting, manufacturing, mining, military, utilities related activities with sub sectors such as:

Appliance and Component (including batteries)

Chemical (including glue, paint, plastics)

Furniture

Electrical Equipment

Fabricated metal

Firefighting

Fueling vehicles an aircraft

Leather and Allied Product

Machinery

Pesticide spraying

Paper

Petroleum

Painting

Printing

Radiator Repair

Solar Cell

Textile and Apparel

Transportation Equipment (e.g. ship and boat building)

Weapons firing

Other risks worsening ototoxicity

Combination with several other risk factors worsens the effect of ototoxicity.

  • Hazardous noise: The effect is synergistic (combined effect greater than individual sum). Several activities listed in table above include combination of ototoxicants and unsafe noise exposures

  • Habits: Such as smoking (including second-hand smoke), vaping, recreational marijuana use, alcohol intake

  • Pre-existing ear conditions: Such as recurrent ear infections, ear damage due to impact, damaged tympanic membrane, pre-existing hearing loss

  • Other: Such as increasing age, gender (males are more susceptible), genetic susceptibility, chronic diseases such as diabetes, hypertension

How you can be affected

Drug induced ototoxicity is dependent on factors such as dose, multiple dosing regimen, duration of therapy, concurrent renal failure (which could lead to drug accumulation), co-administration with other drugs with ototoxic potential.

Chemical induced ototoxicity is generally due to repeated inhalation and skin absorption at doses exceeding safe limits. The effects are amplified as several of these activities are accompanied by unprotected hazardous noise levels.

Health consequences of ototoxicity

Common symptoms of hearing impact include tinnitus (ringing in the ears), ear ache, temporary hearing difficulties and in some cases sudden and permanent hearing loss.

In addition, you could experience temporary vertigo and difficulty maintaining balance and in some cases have severe loss of vestibular sensitivity which may persist permanently. Loss of vestibular sensitivity can cause walking difficulties and oscillopsia (affected eye movement or the eye’s ability to stabilize images).

Loss of hearing can impact social engagement, academic and job performances, pay and career advancements - overall affecting quality of life.

Loss of hearing is also associated with serious conditions such as depression, dementia, increased falls, hospitalizations.

 

DIY-Protection and Prevention

Protection

  • If you have been prescribed an ototoxic drug, discuss with your healthcare provider

  • If you are being exposed to ototoxic chemical(s), seek training on health and safety information and review Safety Data Sheets (SDS)

  • Understand occupational and environmental standards for chemicals and if they are being followed

  • Wear appropriate Personal Protective Equipment including respiratory protection and chemical-protective gloves, arm sleeves, aprons and other appropriate clothing to reduce dermal exposure

  • Wear hearing protection and conduct audiometric testing of noise exposure at your workplace  (i.e., an 85-decibel 8-hour time-weighted average)

  • If you perceive hearing difficulties, self-test with Questionnaire from National Institutes of Health (NIH) and decide on visiting a hearing care professional

Prevention

  • Check if you can replace a hazardous chemical with a less toxic chemical

  • Ensure workplace noise levels align with appropriate safe standards

  • Take steps to control recreational noise exposure by lowering volume, taking listening breaks, distancing yourself from sound source, wearing hearing protection if loud noise is unavoidable

  • Be aware of additional risks worsening ototoxicity that are applicable to your lifestyle and health and discuss with your healthcare provider

  • Get more information on hearing and hearing loss prevention from reliable sources:

Centers for Disease Control and Prevention (CDC). Too Loud! For Too Long! Loud noises damage hearing 

Department of Defense (DoD), Hearing Center of Excellence 

Food and Drug Administration (FDA): What are the signs and symptoms of hearing loss

National Institute for Occupational Safety and Health (NIOSH): Noise and hearing loss prevention

National Institute for Deafness and other Communication Disorders (NIDCD). Noise-induced hearing loss

Occupational Safety and Health Administration (OSHA): Preventing Hearing Loss Caused by Chemical (Ototoxicity) and Noise Exposure

World Health Organization (WHO): World Report on Hearing