Antibiotics are life-saving medications that have helped to treat and cure a range of bacterial infections since their discovery in 1928 by Alexander Fleming.

While they have significantly benefited humanity, they also come with side effects, some of which can be severe. One such side effect that has been reported is hearing loss or damage.

Classification of Antibiotics

Antibiotics can be classified into several groups based on their chemical structure and mechanism of action. The most common classes are:.

Penicillins
Cephalosporins
Macrolides
Tetracyclines
Aminoglycosides
Fluoroquinolones

Hearing Side Effects of Antibiotics

The ototoxicity (hearing loss or damage) caused by antibiotics can be permanent or temporary, depending on the drug, dosage, and individual susceptibility. The following antibiotics are known to have ototoxic potential:.

Aminoglycosides (e.g., gentamicin, streptomycin)
Macrolides (e.g., erythromycin, clarithromycin)
Tetracyclines (e.g., doxycycline)
Fluoroquinolones (e.g., ciprofloxacin, levofloxacin)

The exact mechanism by which antibiotics cause hearing damage is not fully understood, but it is believed to be related to the interference with mitochondrial functions, oxidative stress, and/or excitotoxicity in the inner ear cells.

The hearing loss or damage can occur in one or both ears and may affect different frequencies.

Aminoglycosides

Aminoglycosides are a group of antibiotics that have been used for decades to treat severe bacterial infections, such as meningitis, sepsis, and tuberculosis.

They are highly effective against gram-negative bacteria but can cause serious side effects, including nephrotoxicity (kidney damage) and ototoxicity. Gentamicin is the most commonly used aminoglycoside for ototoxicity testing.

The ototoxicity caused by aminoglycosides is dose-dependent and cumulative, meaning that the higher the dose and the longer the treatment, the greater the risk of hearing loss or damage.

The onset of ototoxicity can occur within days or weeks of treatment and may progress even after the drug is stopped. The symptoms of aminoglycoside ototoxicity include tinnitus (ringing in the ears), vertigo (dizziness), and high-frequency hearing loss.

Macrolides

Macrolides are a class of antibiotics that are commonly used to treat respiratory tract infections, such as pneumonia and bronchitis, as well as skin and soft tissue infections, such as cellulitis and impetigo.

They work by inhibiting bacterial protein synthesis. Erythromycin is the most well-known macrolide for its association with ototoxicity.

The ototoxicity caused by macrolides is rare but can occur, especially in patients with pre-existing hearing loss or renal impairment. The symptoms of macrolide ototoxicity include bilateral sensorineural hearing loss, tinnitus, and vertigo.

Tetracyclines

Tetracyclines are a group of antibiotics that are commonly used to treat acne, rosacea, and other skin infections, as well as respiratory and urinary tract infections. They work by inhibiting bacterial protein synthesis.

Doxycycline is the most commonly prescribed tetracycline for its association with ototoxicity, specifically vestibular/auditory dysfunction.

The mechanism by which tetracyclines cause hearing damage is not fully understood, but it is believed to be related to their chelating properties, which can lead to the accumulation of calcium deposits in the inner ear and the destruction of hair cells. The symptoms of tetracycline ototoxicity include tinnitus, hearing loss, and vertigo.

Fluoroquinolones

Fluoroquinolones are a group of antibiotics that are commonly used to treat various bacterial infections, such as urinary tract infections, respiratory tract infections, and skin and soft tissue infections.

They work by inhibiting bacterial DNA synthesis. Ciprofloxacin is the most commonly prescribed fluoroquinolone for its association with ototoxicity.

The ototoxicity caused by fluoroquinolones is rare but can occur, especially in patients with pre-existing hearing loss or renal impairment. The symptoms of fluoroquinolone ototoxicity include tinnitus, hearing loss, and vertigo.

Prevention and Management of Antibiotic-Induced Hearing Loss

It is important to identify patients who are at high risk of developing antibiotic-induced hearing loss and to monitor their hearing function before, during, and after treatment.

High-risk patients include those with pre-existing hearing loss, renal impairment, or history of noise exposure, as well as neonates and elderly patients.

The prevention and management strategies for antibiotic-induced hearing loss include:.

Using antibiotics only when necessary and for the shortest duration possible.
Choosing antibiotics with minimal ototoxic potential.
Monitoring hearing function with audiometry before, during, and after treatment.
Re-evaluating the drug regimen if hearing loss or damage is suspected.
Treating any underlying infections or conditions that may exacerbate hearing loss.
Providing hearing aids, cochlear implants, or other assistive devices as needed.

Conclusion

Antibiotics are life-saving medications that have revolutionized the treatment of bacterial infections. However, they can also cause side effects, including hearing loss or damage.

It is important to identify high-risk patients, choose antibiotics with minimal ototoxic potential, and monitor hearing function during and after treatment. The prevention and management strategies for antibiotic-induced hearing loss can reduce the risk and severity of this side effect and improve patient outcomes.