Ototoxic

Auditory or vestibular damage (or both) may occur with any aminoglycoside and may be irreversible. Auditory impairment is more likely with amikacin and kanamycin; vestibular dysfunction is more likely with gentamicin and tobramycin Ototoxicity risk is proportional to the plasma levels and thus is especially high if dosage is not appropriately modified in a patient with renal dysfunction. Ototoxicity may be increased by the use of loop diuretics. Because ototoxicity has been reported after fetal exposure, the aminoglycosides are contraindicated in pregnancy unless their potential benefits are judged The antibiotic accumulates in the endolymph and perilymph of the inner ear, and toxicity correlates with the number of destroyed hair cells in the organ of Corti. Patients simultaneously receiving another ototoxic drug, such as cisplatin or the loop diuretics, furosemide, bumetanide, or ethacrynic acid, are particularly at risk. Vertigo and loss of balance (especially in patients receiving streptomycin) may also occur because these drugs affect the vestibular apparatus.