DRUG-INDUCED TINNITUS AND OTHER HEARING DISORDERS

Tinnitus and hearing loss, both reversible and irreversible, are assoc iated both with acute intoxication and long term administration of a l arge range of drugs. The mechanism causing drug-induced ototoxicity is unclear, but may involve biochemical and consequent electrophysiologi cal changes in the inner ear and eighth cranial nerve impulse transmis sion. Over 130 drugs and chemicals have been reported to be potentiall y ototoxic. The major classes are the aminoglycosides and other antimi crobials, anti-inflammatory agents, diuretics, antimalarial drugs, ant ineoplastic agents and some topically administered agents. Prevention of drug-induced ototoxicity is generally based upon consideration and avoidance of appropriate risk factors, as well as on monitoring of ren al function, serum drug concentrations, and cochlear and auditory func tions before and during drug therapy. Ototoxicity, although not life-t hreatening, may cause considerable discomfort to patients taking ototo xic drugs, and in some cases drug discontinuation may be necessary to prevent permanent damage. Much research has been performed to investig ate the causes and mechanisms of ototoxicity, to try to prevent this c omplication. Despite these efforts, ototoxicity still occurs, and ther e is much work to be done in order to understand the mechanism of otot oxicity of different drugs and to prevent hearing loss and tinnitus in the future.