Treatment Effects of Glutamate Antagonist for Tinnitus

Abstract

BACKGROUND AND OBJECTIVES: Tinnitus is one of the most widespread disorders of the auditory system, affecting approximately 17% of the general population, with the frequency increasing to about 33% in the elderly. However, little is known about the underlying physiological mechanism that causes tinnitus and there is no definite treatment. Recently, several studies have showed that subjective tinnitus is mostly generated at the synapse between inner hair cells and their afferent nerves and in addition, some have showed that glutamate is likely to act as the neurotransmitter. The aim of this study has been to evaluate the effective use of caroverine hydrochloride and memantine hydrochloride for tinnitus treatment and to determine their appropriate indication of glutamate antagonist therapy. MATERIALS AND METHOD: From May 1998 through June 2000, 188 patients with subjective tinnitus were treated with caroverine hydrochloride (Spamon(R)). Of the patients, 153 were followed, and 20 of these patients who did not respond to caroverine hydrochloride were treated additionally with memantine hydrochloride (Akatinol(R)). Audiological evaluations were performed in all of the patients. Pre and post-treatment status was analyzed by handicap inventories. RESULTS: Subjective tinnitus was improved in 55 (35.9%) of 153 patients who were treated with caroverine hydrochloride and 11 (55.0%) of 20 patients with memantine hydrochloride. The response group had tendency of shorter duration history of tinnitus than the non-response group. There was no difference between the response group and the non-response group in age, sex, site, and tinnitus characteristics. CONCLUSION: We suggest that glutamate antagonists such as caroverine hydrochloride and memantine hydrochloride can be used as an alternative modality for treatment of subjective tinnitus.