Review of Pharmacotherapy for Tinnitus

Various medications are currently used in the treatment of tinnitus, including anesthetics, antiarrhythmics, anticonvulsants, antidepressants, antihistamines, antipsychotics, anxiolytics, calcium channel blockers, cholinergic antagonists, NMDA antagonists, muscle relaxants, vasodilators, and vitamins. To date, however, no medications have been specifically approved to treat tinnitus by the US Food and Drug Administration (FDA). In addition, medicines used to treat other diseases, as well as foods and other ingested materials, can result in unwanted tinnitus. These include alcohol, antineoplastic chemotherapeutic agents and heavy metals, antimetabolites, antitumor agents, antibiotics, caffeine, cocaine, marijuana, nonnarcotic analgesics and antipyretics, ototoxic antibiotics and diuretics, oral contraceptives, quinine and chloroquine, and salicylates. This review, therefore, describes the medications currently used to treat tinnitus, including their mechanisms of action, therapeutic effects, dosages, and side-effects. In addition, this review describes the medications, foods, and other ingested agents that can induce unwanted tinnitus, as well as their mechanisms of action.

Drug therapy and tinnitus: the UK experience

There have been five recent studies of drug treatment in tinnitus in the UK using Class I anti-arrhythmic preparations. We present a new double-blind study of tocainide hydrochloride in severe, unmaskable tinnitus. No significant response is noted in any of the controlled trials to the active ingredient, and more work is needed on diagnostic criteria to see if those who do respond constitute a separate group. There was a surprisingly low incidence of placebo response and the importance of the side effects produced by the drugs in this group is stressed. The finding that three patients with profound hearing losses have had some continued benefit leads to the cautious conclusion that drug responders may be have a central component to their tinnitus.

Medical treatment of tinnitus

One of the most frustrating clinical problems for both otolaryngologist and patient is having to deal with the symptom of tinnitus. From the patient's point of view, frustration stems from the fact that this often unrelenting symptom can lead to a total disruption of a productive lifestyle, and in a number of instances, proves to be a tragically fatal symptom as the patients turn to suicide as a final solution. The otolaryngologist has been frustrated because until recently he has had little more than sympathy to offer the patient. This has led to a helpless feeling between both parties.

Tinnitus in children with hearing loss

The results are reported of a survey of tinnitus in deaf children in secondary-school age. Of 158 children in five units for the partially hearing and two schools for the deaf. 78 were found to have tinnitus. The tinnitus was constant in two children and intermittent in the remaining 76. The frequency with which the tinnitus occurred, and its duration and loudness, are reported. Some children claimed that tinnitus reduced their hearing ability and speech discrimination. It some, tinnitus was associated with headache or vertigo. When it was unilateral, tinnitus was more commonly on the side of the better-hearing ear. A group of children was defined in whom the tinnitus had features that made it a particularly troublesome symptom.

Acoustic correlates of tonal tinnitus

A sensitive microphone has been developed which can pick up tonal signals (spontaneous acoustic emissions) in the sealed ear-canal of certain subjects. Various properties of these frequency components suggest that they arise from an active, frequency-selective self-limiting feedback process within the cochlea and that they rely on internal reflection from the middle ear. An external tone can synchronize, frequency-lock, suppress of frequency-shift the acoustic component. These interactions are frequency-dependent in a way suggestive of cochlear tuning properties. Positive or negative middle-ear pressure can also influence the components by increasing their frequency and in some cases can enhance one component at the expense of a neighbouring one. Some subjects hear these components as tinnitus and can report on the measured changes. Other subjects do not hear the measured signals, which otherwise behave similarly. A third group of subjects have tinnitus but no objective sound can be detected. In this last group there are, nevertheless, sometimes notches or other discontinuities in the audiogram which correspond to their tinnitus pitch-matches. It appears likely that the recordable type of tinnitus is essentially non-pathological and represents hypersensitivity of the system, whereas the non-recordable type might be associated with local pathological changes at the end-organ or more centrally.

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.

Scanning electron microscopic findings in respiratory nasal mucosa following cigarette smoke exposure in rats

In the present study, the respiratory epithelium of the nasal mucosa of rats that had been exposed to cigarette smoke was examined by scanning electron microscope (SEM). Some significant morphological changes such as increased mucociliar activity, compound cilia, disorientation, short cilia and protrusive Goblet cells were observed.

Retest stability of the tinnitus handicap questionnaire

The test-retest stability of the Tinnitus Handicap Questionnaire was assessed for a sample of 32 tinnitus patients. The questionnaire is a self-report measure that quantifies the physical, emotional, and social consequences of tinnitus (factor 1), the interfering effects of tinnitus on the hearing ability of the patient (factor 2), and the patients' view of tinnitus (factor 3). Retest stability estimates were obtained in order to determine the applicability of using the questionnaire as an outcome measure following tinnitus management. High test-retest correlations emerged for factors 1 and 2, whereas factor 3 yielded inadequate retest reliability. Therefore, it is recommended that only factors 1 and 2 be used for documenting changes in self-perceived tinnitus handicap following medical, surgical, or rehabilitative intervention.

Tinnitus

Tinnitus, a common complaint, reportedly affects more than 37 million Americans. Most often, it is associated with a sensorineural hearing loss in the high-frequency range. Tinnitus, however, is a symptom and not a disease. Complacency about this symptom complex may cause physicians to overlook a severe underlying pathologic process. Patients with unilateral tinnitus, pulsatile tinnitus, fluctuating tinnitus, or tinnitus associated with vertigo should undergo thorough assessment, including elicitation of a complete history, physical examination, and audiologic analysis. In many instances, treatment is effective. Masking of tinnitus, medical therapy, and biofeedback and counseling are some measures that have been used in the management of tinnitus.

Systemic local anesthetics in pain control

Analgesia has been reported as a potential effect of systemically administered local anesthetics for over four decades. Interest in the use of these drugs as analgesics has been stimulated by the advent of oral formulations and the findings of several controlled studies that suggest efficacy of these preparations in neuropathic pain syndromes. We review the pharmacology of local anesthetics and critically evaluate the medical literature describing the analgesic consequences of systemic administration. The data extant support their analgesic effect in selected pain syndromes.

Vestibular effects of intravenous lidocaine used in the treatment of tinnitus

Intravenous lidocaine is known to have an effect on the auditory system in that it is useful for suppressing tinnitus, albeit temporarily. We have used intravenously administered lidocaine as one of the treatment modalities for refractory, disturbing, tinnitus. Its effects on the vestibulo-ocular system were determined by electronystagmography performed before and immediately after injecting lidocaine: smooth pendular stimulus tracking was unaffected; spontaneous and positional nystagmus tended to be suppressed; directional preponderance was reduced or reversed; and the difference between the nystagmus responses in the two directions during the pendular rotation chair test was also reduced or reversed. These changes in the caloric and rotation tests were statistically significant. Lidocaine also appeared to have altered the balance between the two sides in the vestibulo-spinal system as indicated by the results of the stepping test during craniocorpography. The results lend support to the hypothesis that intravenous lidocaine acts at the level of the central nervous system rather than at the periphery.

Alzheimer's disease may begin in the nose and may be caused by aluminosilicates

Genetic factors may interact with aging changes in the nasal mucociliary apparatus to increase the probability that ubiquitously occurring aluminosilicates may enter sensory neurons of the olfactory epithelium and spread transneuronally to several olfactory-related areas of the brain, thereby initiating changes that eventually result in neuronal damage typical of Alzheimer's disease. A speculative sequence of events is suggested by which neuronally-contained aluminosilicates might cleave or otherwise alter a normal cellular protein in such a manner that aggregates would arise that could interfere with cellular function and which also could act in a pseudo-infective manner, relaxing translational and transcriptional controls in the synthesis of the native protein. Some relevant experiments and potential therapies arising from the hypothesis presented are discussed.

Electrocochleographic findings and the effects of lidocaine on tinnitus in non-hearing ears

In the preceeding report (Jackson, 1985) the author produced evidence which brought into question the widely held view that, in abolishing tinnitus, lidocaine was acting 'centrally'. This present investigation is another approach to attempt to narrow the site of action of lidocaine in abolishing tinnitus. During a four-year period, patients suffering from strictly unilateral tinnitus which was referred to, and therefore apparently arising from, an ipsilateral 'dead' ear, underwent electrocochleography. Additionally, the subjective effect on the tinnitus of a bolus injection of lidocaine was recorded. Nine patients were available for this study, which appears to show a correlation of the results of the electrocochleogram and the effects of the lidocaine injection, although the numbers are small.

A comparison of the effects of eighth nerve section with lidocaine on tinnitus

The success rate of eighth nerve section in abolishing tinnitus is disappointing and the results generally unpredictable. A comparison of the effects of a bolus intravenous injection of lidocaine with the effects of nerve section is reported: it presents some evidence that the response to lidocaine may be of value in selecting patients for nerve section, and further it may shed some light on the site of action of lidocaine in suppressing tinnitus.

The value of tocainide in the treatment of tinnitus. A double-blind controlled study

We assessed the value of tocainide in the treatment of tinnitus by performing a double-blind controlled trial in which each of 48 patients with annoying tinnitus received either tocainide HC1 900 mg/day or a placebo. Before the trial, the effect of intravenous lidocaine was evaluated in each patient so that both lidocaine and tocainide could be compared in altering tinnitus. We found that tocainide appeared to have no better effect than the placebo, whereas lidocaine suppressed tinnitus in 81% of the patients treated. The mechanisms of action of both drugs as well as their influence on tinnitus are discussed, as are the side effects of tocainide.

Psychological treatment of tinnitus. An experimental group study

Twenty-four patients with moderately severe (grade 2) to severe (grade 3) subjective tinnitus participated in an experimental group study. The patients were randomly assigned to a treatment group and a waiting-list control group. Treatment was given with a coping technique and comprised 10 one-hour sessions. Following a corresponding period without treatment, the control group was treated similarly. Daily self-recording of the subjective tinnitus loudness, the discomfort from the tinnitus, depression and irritation was performed before and after treatment. In addition, psychoacoustic measurement was undertaken on three occasions. The treatment group improved significantly more than the waiting-list control group. After treatment of the latter group, combined data of both groups showed statistically significant improvements in all variables. The results show that tinnitus annoyance can be treated by psychological methods.

Placebo effect in tinnitus management

Masking devices, lidocaine, and analog oral forms of lidocaine have all been reported as being effective forms of therapy to relieve tinnitus. Many studies, however, have used single-blind protocols and were possibly biased by placebo effects. To investigate the contributions of a placebo effect in clinical tinnitus studies, 25 tinnitus patients who had received a placebo injection in a previous double-blind lidocaine study were contacted on the pretense that they would receive a test dose of lidocaine; the 20 who responded were included in this study. A 5 cc bolus of placebo saline solution instead of lidocaine was then administered to each patient. Forty percent of the patients reported a change in their tinnitus following the placebo injection. The results of this study serve to point out the inherent flaws in straight clinical trials, and that the success rates achieved in such uncontrolled clinical investigations may be biased by the placebo effects.

The effect of intra-venous lidocaine and several different doses oral tocainide HCl on tinnitus. A dose-finding study

As part of preliminary studies for an investigation to assess the place of some drugs, including tocainide HCl, in the treatment of tinnitus, the present study was performed to establish the appropriate dose for tocainide. The effect of lidocaine HCl on tinnitus was studied in a double-blind controlled cross-over study in 22 patients. Lidocaine appeared to give significant relief. To select an optimal daily dose for the lidocaine analog tocainide HCl, this drug was administered orally to 19 patients with obstructive tinnitus in seven 4-day periods. This could be done in a single-blind controlled trial. A different dose was given in each period. Comparison of the effect on tinnitus and the associated side effects led to the choice of a daily dose of 900 mg. The effect of lidocaine HCl appeared to have no prognostic value for the effect of tocainide HCl on the tinnitus in the individual patient.

Treatment of tinnitus with intravenous lidocaine: a double-blind randomized trial

Several recent reports have suggested that intravenous (IV) lidocaine is an effective form of therapy to relieve tinnitus; however, many of these studies were not well controlled. A double-blind randomized trial to assess the effectiveness of IV lidocaine on tinnitus was conducted at the University of Washington-affiliated hospitals on a total of 50 patients. Tinnitus was evaluated before and after injection by subjective assessment and audiometric matching. Although 40% of the lidocaine group reported a decrease in tinnitus, over 30% of the lidocaine group reported increased tinnitus after administration of the drug. There was also a high incidence of side effects, including disequilibrium, slurred speech, numbness, and tingling of the extremities in the drug group. The results of the study suggest that the clinical usefulness of IV lidocaine in relieving tinnitus may be less than was previously reported.

Medical treatment of tinnitus

Medical treatment is presented as the best hope of the various treatment methods available for the management of tinnitus. A test dose of 100 mg lidocaine given rapidly intravenously will give good or partial temporary relief to approximately 80% of patients with tinnitus. More permanent relief can then be achieved by the oral anticonvulsants carbamazepine or primidone but the side effects of these drugs are occasionally too severe to justify their use. Three preliminary clinical studies of the oral amide of lidocaine, tocainide hydrochloride, were conducted and results with 600 mg four times daily are very promising. Further long-term clinical trials with tocainide will be started soon. It would appear that local anesthetics when given intravenously block the multisynaptic slow pathways in tinnitus as well as in chronic pain, with which there are many other similarities. The delay in wave V in the BSER and the sudden sleep induced in patients with a good response to intravenous lidocaine further confirm the site of action of these drugs in the brainstem and reticular formation. Until tocainide is available for general use it is possible to control tinnitus with large doses of intravenous lidocaine, 100 mg given rapidly and 400 mg slowly with EKG monitoring each day for several days, and then at weekly intervals, as in the treatment of clausalgia. Because patients with disabling tinnitus, as with chronic intractable pain, are rigid, insecure, chronically depressed and fatigued, a mood-elevating tranquilizer drug combination such as perphenazine-amitriptyline is of great value in maintaining these patients. While medical treatment is not the final answer it is the best treatment available and it offers a promising direction for further study.