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TinnitusPhase 4NCT03365011

Nitrous Oxide Treatment for Tinnitus

A Phase 4 study testing Nitrous oxide gas for inhalation in people with Tinnitus, run by Washington University School of Medicine at 1 site in United States.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

Tinnitus is perception of sound without the presence of an external acoustic stimulus. Approximately 50 million Americans experience chronic tinnitus and of these, 10 million have bothersome tinnitus. The tinnitus research literature suggests that NMDA receptor antagonists may prove to be useful in reducing tinnitus. Read more about this study

Who is it for?
Ages 18 to 65 yearsHealthy volunteers can take part
Conditions the study is for
Tinnitus
What is being tested?
Nitrous oxide gas for inhalation
Could I receive a placebo?
Yes, some participants may receive a placebo
How many people
40 participants
Where
1 siteUnited States
Study dates
Oct 2016to Jul 2017
Phase
Phase 4
Are there results?
Yes, posted in the registrySummary in the doctors' view

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 to 65 years
  • All sexes
  • Healthy volunteers accepted
  • Adult, Older adult

Who may be able to join

  • Adult men and women 18-65 years of age
  • Subjective, unilateral or bilateral, non-pulsatile tinnitus scoring "Bothered more than a little but not a lot", "Bothered a lot", or "Extremely bothered" on the Global Bothersome scale
  • Able to give informed consent
  • Must be able to read, write, and understand English

Who cannot join

  • Bipolar disorder
  • Schizophrenia
  • Schizoaffective disorder
  • Substance abuse or dependence (except for remote substance abuse or dependence with remission at least 1 year prior to the study and except for nicotine use disorders)
  • Acute medical illness that may pose subject at risk during nitrous oxide administration
  • Active psychotic symptoms
Show all 19Show fewer
  • Patients with significant pulmonary disease and/or requiring supplemental oxygen
  • Contraindication against the use of nitrous oxide:
  • Pneumothorax
  • Bowel obstruction
  • Middle ear occlusion
  • Elevated intracranial pressure
  • Chronic cobalamin and/or folate deficiency treated with folic acid or vitamin B12
  • Pregnant patients
  • Breastfeeding women
  • Previous administration of NMDA-receptor antagonists (e.g., ketamine) within the last 3 months
  • Tinnitus related to cochlear implantation, retrocochlear lesion, Meniere's Disease, or other known anatomic lesions of the ear or temporal bone
  • Tinnitus related to a Workman's Compensation claim or litigation-related event that is still pending.
  • Any medical condition, which, in the opinion of the PI, confounds study results or places the subject at greater risk

Trial locations and contacts

1 site in 1 country.

United States1 site
  • Washington University School of Medicine

    St Louis, Missouri, 63110

Other trials in United States

About this study

Official title: Nitrous Oxide as Treatment for Tinnitus: A Randomized Crossover Trial

Tinnitus is perception of sound without the presence of an external acoustic stimulus. Approximately 50 million Americans experience chronic tinnitus and of these, 10 million have bothersome tinnitus. The tinnitus research literature suggests that NMDA receptor antagonists may prove to be useful in reducing tinnitus. Nitrous oxide, a member of the NMDA receptor antagonist class, is a widely-used general anesthetic and sedative with a proven safety profile. The investigators hypothesized that the administration of nitrous oxide, an NMDA receptor antagonist, may be effective in treatment of tinnitus. The study design was a randomized placebo-controlled crossover trial.

Read the detailed description

Subjective, idiopathic, non-pulsatile tinnitus ("tinnitus") is perception of sound without the presence of an external acoustic stimulus. Approximately 50 million Americans experience chronic tinnitus and of these, 10 million have bothersome tinnitus. Bothersome tinnitus is associated with poorer working memory, slower processing speeds and reaction times, and deficiencies in selective attention.

Currently, effective therapies for tinnitus remain limited. Examples of therapies include external sound therapy to mask the perceived sound, behavioral therapy to habituate the patient to the perceived sound, and counseling such as cognitive behavioral therapy to address the bother and impact that tinnitus has on people's lives. Surgical treatment such as nerve transection remains controversial given its lack of efficacy and adverse event profile. There are no drugs approved by the FDA for the treatment of tinnitus. Antidepressant and antianxiety medications are prescribed to patients with tinnitus with limited benefit.

Nitrous oxide is an N-methyl-D-aspartate (NMDA) receptor antagonist, a class of drugs shown to have antidepressant effects. A previous trial examined the use of nitrous oxide as a treatment for major depressive disorder (MDD). Generally, NMDA receptors promote excitation at synapses throughout the auditory pathway and play diverse roles in synaptic development and auditory information processing. In the setting of chronic damage to the auditory system, overactivation of NMDA receptors leads to aberrant spontaneous neuronal firing in the cochlea and auditory brainstem structures, which can further perpetuate damage and disease in a feed-forward mechanism. Studies by Guitton et al. and Puel et al. showed that administration of NMDA receptor antagonists prior to the administration of salicylate was effective in preventing acute excitotoxic tinnitus, establishing that salicylate induces tinnitus through its action on NMDA receptors. Thus, NMDA receptors are thought to be implicated in the generation and perpetuation of several auditory diseases including tinnitus. The investigators hypothesized that the administration of nitrous oxide, an NMDA receptor antagonist, may be a therapeutic strategy in the treatment of tinnitus.

The study was a randomized placebo-controlled crossover trial. Each participant attended two intervention sessions, one "treatment" and one "placebo". Participants eligible to participate in the study were randomly assigned to receive either placebo followed by nitrous oxide or nitrous oxide followed by placebo, according to a computer-generated randomization sequence. Only the statistician and the anesthesiology team directly involved in administration of nitrous oxide and placebo had access to the group assignments. All participants and other study team members administering survey assessments remained blinded. The two intervention sessions were held at least two weeks apart and were indistinguishable in setting, setup, and monitoring in order to maintain blinding for the participants and study team members. All intervention sessions were performed at the Washington University Clinical Research Unit, a component of the Center for Applied Research Sciences.

Conditions
Tinnitus
Being tested
Nitrous oxide gas for inhalation, Placebo gas for inhalation
Keywords
Nitrous Oxide
Medical subject headings
Tinnitus

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • Nitrous oxide gas for inhalationDrug

    Nitrous oxide gaseous mixture (50% nitrous oxide and 50% oxygen) for 40 minutes duration under anesthesia supervision with monitoring according to standards set by the American Society of Anesthesiologists.

  • Placebo gas for inhalationDrug

    Placebo gaseous mixture (50% nitrogen and 50% oxygen) for 40 minutes duration under anesthesia supervision with monitoring according to standards set by the American Society of Anesthesiologists.

Study groups in NCT03365011
Study groupRoleWhat they receive
PlaceboPlacebo comparatorPlacebo was defined as 50% nitrogen and 50% oxygen for 40 minutes. Participants are blinded to the order of interventions administered. Participants have been informed prior to consent that one session will contain the nitrous oxide gas mixture, and the other session will contain the placebo gas mixture.
Receives: Drug: Placebo gas for inhalation
Nitrous oxideExperimentalNitrous oxide treatment was defined as 50% nitrous oxide and 50% oxygen for 40 minutes. Participants are blinded to the order of interventions administered. Participants have been informed prior to consent that one session will contain the nitrous oxide gas mixture, and the other session will contain the placebo gas mixture.
Receives: Drug: Nitrous oxide gas for inhalation

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Change in Tinnitus Functional Index (TFI) Score

    Change of participant-reported tinnitus symptoms 1 week after each intervention.

    The Tinnitus Functional Index (TFI) is a 25-question survey assessing tinnitus impact on quality of life. Participants were asked to rate on a scale from 0-10 the degree of unpleasantness, cognitive interference, sleep disturbance, auditory difficulties, interference with relaxation, and emotional distress associated with their tinnitus. Subscores are summed and scaled to a score of 0-100. A score less than 25 indicates mild problems due to tinnitus and little need for intervention, while a score between 25-50 indicates significant problems due to tinnitus with potential need for intervention.

    A decrease in TFI score indicates decreased bother due to tinnitus over time, a better outcome. An increase in TFI score indicates increased bother due to tinnitus over time, a worse outcome.

    Measured: Pre-intervention and 1 week post-intervention

Secondary outcomes (2)
  1. Change in Global Bothersome Scale (GBS) Score

    Change in participant-reported tinnitus bother after each intervention.

    Global Bothersome Scale (GBS) measured participant's self-assessment of tinnitus bother on a 5-point scale ranging from "Not bothered, 0" to "Extremely bothered, 5."

    A change of 0 indicates no change in tinnitus bother over time. A change of -1 indicates somewhat improved tinnitus bother, and a change of positive 1 indicates somewhat worsened tinnitus bother. A change of positive 2 indicates significantly worsened tinnitus bother.

    Measured: Pre-intervention and 1 week post-intervention

  2. Patients' Global Impression of Change

    Participant-reported perception of change in impact of tinnitus on quality of life since receiving each intervention

    Measured: 1 week post-intervention

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted7 Dec 2017
  2. Study startOct 2016
  3. Primary completionJun 2017
  4. Study completionJul 2017

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase 4
Primary purpose
Treatment
Allocation
Randomised
Intervention model
Crossover
Masking
Double blind
Who is masked
Participant, Investigator
Enrolment
40 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT03365011
Sponsor's protocol ID
201606104
Status last verified
Nov 2018
First submitted
15 May 2017
Last updated
14 Dec 2018
Individual data sharing
No

Publications

  • Shargorodsky J, Curhan GC, Farwell WR. Prevalence and characteristics of tinnitus among US adults. Am J Med. 2010 Aug;123(8):711-8. doi: 10.1016/j.amjmed.2010.02.015.

    PubMed 20670725
  • Pierce KJ, Kallogjeri D, Piccirillo JF, Garcia KS, Nicklaus JE, Burton H. Effects of severe bothersome tinnitus on cognitive function measured with standardized tests. J Clin Exp Neuropsychol. 2012;34(2):126-34. doi: 10.1080/13803395.2011.623120. Epub 2011 Dec 14.

    PubMed 22168528
  • Tunkel DE, Bauer CA, Sun GH, Rosenfeld RM, Chandrasekhar SS, Cunningham ER Jr, Archer SM, Blakley BW, Carter JM, Granieri EC, Henry JA, Hollingsworth D, Khan FA, Mitchell S, Monfared A, Newman CW, Omole FS, Phillips CD, Robinson SK, Taw MB, Tyler RS, Waguespack R, Whamond EJ. Clinical practice guideline: tinnitus. Otolaryngol Head Neck Surg. 2014 Oct;151(2 Suppl):S1-S40. doi: 10.1177/0194599814545325.

    PubMed 25273878
  • Langguth B, Elgoyhen AB. Current pharmacological treatments for tinnitus. Expert Opin Pharmacother. 2012 Dec;13(17):2495-509. doi: 10.1517/14656566.2012.739608. Epub 2012 Nov 4.

    PubMed 23121658
  • Beebe Palumbo D, Joos K, De Ridder D, Vanneste S. The Management and Outcomes of Pharmacological Treatments for Tinnitus. Curr Neuropharmacol. 2015;13(5):692-700. doi: 10.2174/1570159x13666150415002743.

    PubMed 26467416
  • Jevtovic-Todorovic V, Todorovic SM, Mennerick S, Powell S, Dikranian K, Benshoff N, Zorumski CF, Olney JW. Nitrous oxide (laughing gas) is an NMDA antagonist, neuroprotectant and neurotoxin. Nat Med. 1998 Apr;4(4):460-3. doi: 10.1038/nm0498-460.

    PubMed 9546794
  • Nagele P, Duma A, Kopec M, Gebara MA, Parsoei A, Walker M, Janski A, Panagopoulos VN, Cristancho P, Miller JP, Zorumski CF, Conway CR. Nitrous Oxide for Treatment-Resistant Major Depression: A Proof-of-Concept Trial. Biol Psychiatry. 2015 Jul 1;78(1):10-18. doi: 10.1016/j.biopsych.2014.11.016. Epub 2014 Dec 9.

    PubMed 25577164
  • Sanchez JT, Ghelani S, Otto-Meyer S. From development to disease: diverse functions of NMDA-type glutamate receptors in the lower auditory pathway. Neuroscience. 2015 Jan 29;285:248-59. doi: 10.1016/j.neuroscience.2014.11.027. Epub 2014 Nov 25.

    PubMed 25463512
  • Kaltenbach JA, Zhang J, Finlayson P. Tinnitus as a plastic phenomenon and its possible neural underpinnings in the dorsal cochlear nucleus. Hear Res. 2005 Aug;206(1-2):200-26. doi: 10.1016/j.heares.2005.02.013.

    PubMed 16081009
  • Sahley TL, Nodar RH, Musiek FE. Endogenous dynorphins: possible role in peripheral tinnitus. Int Tinnitus J. 1999;5(2):76-91.

    PubMed 10753426
  • Nicolas-Puel C, Faulconbridge RL, Guitton M, Puel JL, Mondain M, Uziel A. Characteristics of tinnitus and etiology of associated hearing loss: a study of 123 patients. Int Tinnitus J. 2002;8(1):37-44.

    PubMed 14763234
  • Guitton MJ, Dudai Y. Blockade of cochlear NMDA receptors prevents long-term tinnitus during a brief consolidation window after acoustic trauma. Neural Plast. 2007;2007:80904. doi: 10.1155/2007/80904.

    PubMed 18301716
  • Puel JL. Cochlear NMDA receptor blockade prevents salicylate-induced tinnitus. B-ENT. 2007;3 Suppl 7:19-22.

    PubMed 18225604
  • Guitton MJ, Caston J, Ruel J, Johnson RM, Pujol R, Puel JL. Salicylate induces tinnitus through activation of cochlear NMDA receptors. J Neurosci. 2003 May 1;23(9):3944-52. doi: 10.1523/JNEUROSCI.23-09-03944.2003.

    PubMed 12736364
  • Guitton MJ. Tinnitus: pathology of synaptic plasticity at the cellular and system levels. Front Syst Neurosci. 2012 Mar 8;6:12. doi: 10.3389/fnsys.2012.00012. eCollection 2012.

    PubMed 22408611

Questions about this trial

What is this clinical trial studying?

A Phase 4 study testing Nitrous oxide gas for inhalation in people with Tinnitus, run by Washington University School of Medicine at 1 site in United States.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 4 inclusion and 19 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 14 Dec 2018. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 4 studies take place after a treatment is approved, to learn more about its long-term benefits and risks in everyday use.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

Yes. Results are posted in the registry (first posted 6 Nov 2018). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Change in Tinnitus Functional Index (TFI) Score (time frame: Pre-intervention and 1 week post-intervention). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT03365011, which also lists 22 linked publications.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 14 Dec 2018.

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