Symptoms are frequently present at the onset of measurable hearing loss. Risk factors for ototoxicity include renal insufficiency, intravenous bolus, co-administration with aminoglycosides, and increased cumulative doses. An audiogram should be obtained at the onset of therapy, before each successive dose, and with the onset of symptoms. Salycilates have been used for more than 100 years and have long been known to produce reversible hearing loss associated with tinnitus. The mechanism of action is thought to involve vasoconstriction of capillaries in the stria vascularis.
Symptoms resolve following cessation of therapy.
However, several cases of irreversible SNHL and tinnitus have been reported. Monitoring for ototoxicity should be individualized to the drug and to the patient. The early symptoms seen with some drugs, such as the salycilates and quinine, obviate the need for formal monitoring. The profound, irreversible effects seen with drugs such as the aminoglycosides and cis -platinum require much more formal monitoring. He had no prior otologic history, including surgery, noise exposure, or ototoxic drugs.