Local anaesthetics and tinnitus. Proposed peripheral mechanism of action of lidocaine.

To elucidate the question whether lidocaine reduces tinnitus by a central or by a peripheral mechanism of action, its effect on tinnitus was compared with that of QX-572, a quaternary ammonium derivative of lidocaine which does not readily penetrate the blood-brain barrier. The results of experimental as well as clinical investigations indicate that the effects of lidocaine and QX-572 on tinnitus are mediated by a peripheral mechanism possibly related to their accumulation on inner ear melanin.