Furosemide ototoxicity: clinical and experimental aspects

Area of Science:

• Ototoxicology
• Pharmacology
• Auditory Neuroscience

Background:

• Furosemide is a diuretic known to cause ototoxicity.
• Its effects on cochlear function include reversible changes in electrical potentials and ion concentrations.

Purpose of the Study:

• To investigate the ototoxic effects of furosemide alone and in combination with kanamycin.
• To elucidate the pharmacological mechanisms underlying furosemide-induced hearing loss.

Main Methods:

• Administration of furosemide and kanamycin to experimental animals.
• Measurement of endocochlear potential, eighth nerve action potential, and endolymph potassium concentration.
• High-performance liquid chromatography (HPLC) was used to measure kanamycin blood levels.

Main Results:

• Furosemide alone caused reversible decreases in cochlear potentials and endolymph potassium.
• The combination of kanamycin and furosemide resulted in irreversible cochlear dysfunction.
• Elevated blood and perilymph kanamycin levels correlated with irreversible ototoxicity.

Conclusions:

• Kanamycin potentiates the ototoxic effects of furosemide, leading to permanent hearing loss.
• Measured kanamycin blood levels align with clinically observed ototoxic thresholds.
• These findings provide a pharmacological explanation for furosemide-induced hearing impairment.