Phase 4 N=40 Randomized Double-blind Treatment

Nitrous Oxide Treatment for Tinnitus

Tinnitus

Bottom Line

View on ClinicalTrials.gov: NCT03365011 ↗

Enrolled (actual)

Serious AEs

0.0%

Results posted

Nov 2018

Primary outcome: Primary: Change in Tinnitus Functional Index (TFI) Score — -1.8; -2.5 score on a scale

Study Design & Population

Study type: Interventional
Phase: Phase 4
Interventions: Nitrous oxide gas for inhalation (Drug); Placebo gas for inhalation (Drug)
Age: Adult, Older Adult · 18+ yrs
Sex: All
Sponsor: Washington University School of Medicine
Primary completion: Jun 2017

Outcome Measures

Outcome	Result	p-value
PRIMARY Change in Tinnitus Functional Index (TFI) Score	-1.8; -2.5	—
SECONDARY Change in Global Bothersome Scale (GBS) Score	5; 2; 28; 34; 5; 2	—
SECONDARY Patients' Global Impression of Change	24; 20; 5; 10; 2; 2	—

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. 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.

Eligibility Criteria

Inclusion Criteria

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

Exclusion Criteria

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
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

View full record on ClinicalTrials.gov →

Data sourced from ClinicalTrials.gov (NCT03365011). Outcome figures and adverse-event rates are extracted automatically from the registry's posted results and are provided for clinician reference, not as a substitute for the primary publication.