Drugs in the treatment of tinnitus.

Many drugs and some foods can cause or aggravate tinnitus in some patients. These substances should be identified and withdrawn. Tinnitus may be improved by the treatment of associated conditions, infections, or hearing loss with appropriate drugs--hypotensives, antibiotics, vasodilators, fluoride or thyroxine. Intravenous lignocaine can temporarily reduce or abolish tinnitus in many patients but can aggravate existing tinnitus in some and may have no effect on others. Analogy with pain of central origin suggests that the beneficial effects of lignocaine (lidocaine) may be due to its anticonvulsant action. Lignocaine is used as a test to distinguish between different mechanisms of tinnitus and to predict responses to oral anticonvulsants. Dramatic responses with lignocaine are usually associated with cochlear hearing loss and often with comparable though less marked responses to oral anticonvulsants. Patients who do not benefit from lignocaine do not respond to oral anticonvulsants. The action of anticonvulsants is often potentiated by tricyclic antidepressants. The majority of patients who respond to lignocaine can also have their tinnitus effectively masked, as predicted, on a tinnitus synthesizer. A small proportion respond to masking and not to lignocaine and a small proportion to lignocaine and not to masking. Beneficial effects of masking and anticonvulsants are cumulative. Anticonvulsants may also produce subjective improvement in clarity, improved tolerance of hearing aids and increased masking benefit when a hearing aid is worn.