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Completed

NCT Number: NCT07772089

Acute Nicotine Gum and Tinnitus Loudness in Non-Smoking Adults

This study tested whether a single dose of nicotine gum can reduce the loudness of tinnitus (ringing in the ears) in non-smoking adults with chronic tinnitus. Nicotine acts on brain nicotinic acetylcholine receptors that regulate the balance of excitation and inhibition in auditory and attention networks, and may temporarily quiet the phantom sound while improving the ability to focus on relevant sounds. Using a double-blind, placebo-controlled, within-subject crossover design, each participant attended two sessions and received a single 4 mg dose of nicotine polacrilex gum at one session and a flavor-matched placebo gum at the other, in random order. The primary measure was the within-session change in a psychoacoustic match of tinnitus loudness; auditory selective attention was a secondary measure.

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Key information

Conditions

Tinnitus Chronic Subjective Tinnitus Ear Diseases Hearing Disorders Nervous System Diseases Neurologic Manifestations Otorhinolaryngologic Diseases Pathological Conditions, Signs and Symptoms Sensation Disorders Signs and Symptoms

Age range

18 year–80 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 1 / Phase 2

Primary location

San Diego State University

San Diego, California, 92182, United States

About this study

Background: Tinnitus is associated with excitatory-inhibitory imbalance across auditory, attentional, and limbic circuits. Nicotinic acetylcholine receptor modulation is a candidate dual-target mechanism, but it has not been evaluated for tinnitus in humans.

Dose and protocol: The 4 mg dose and a standardized administration protocol (continuous chewing for 20 minutes at one chew per second, paced by a 1 Hz auditory cue, with saliva retained and spitting minimized to maximize buccal absorption) were established in a preceding gum optimization study in non-smokers.

Trial design: Randomized, double-blind, placebo-controlled, within-subject crossover. Each participant attended two sessions on separate days, separated by a washout of at least 72 hours, receiving nicotine gum at one session and matched placebo gum at the other in randomized 1:1 order. Allocation was concealed with sequentially numbered, opaque, sealed envelopes; an independent examiner prepared the gum and participants wore a blindfold during administration.

Outcomes: The primary outcome was the within-session change (post minus pre) in psychoacoustic tinnitus loudness match, compared between the nicotine and placebo sessions. The secondary outcome was the within-session change in auditory selective attention (Coordinate Response Measure percent correct). Additional pre-specified measures were pure-tone audiometry, the Tinnitus Handicap Inventory, and the Tinnitus Functional Index. Outcomes were analyzed with generalized linear mixed models.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Non-smoking adult, defined as fewer than 100 cigarettes in a lifetime and none in the past year, with a Fagerstrom Test for Nicotine Dependence score of 2 or less and a negative urinary cotinine test
  • Chronic subjective tinnitus of at least 6 months' duration

Exclusion criteria

  • Current or recent tobacco or nicotine use
  • Pregnancy or breastfeeding
  • Unstable cardiovascular disease
  • Any condition precluding the psychoacoustic tasks

Treatment and study plan

Nicotine polacrilex gum 4 mg

Drug

A single 4 mg dose (one 4 mg piece) of mint nicotine polacrilex gum, chewed continuously for 20 minutes at one chew per second with saliva retained.

Other names: Nicorette

Placebo gum

Other

Flavor-matched sugar-free mint gum (Trident) matched to the nicotine gum in shape, flavor, color, and texture, chewed under the identical protocol.

Primary outcomes

  1. Within-session change in psychoacoustic tinnitus loudness match (nicotine vs placebo)

    Time frame: Baseline (pre-administration) and up to 2 hours after gum administration

    Tinnitus loudness was matched to the participant's tinnitus pitch by a method-of-adjustment procedure and expressed in dB sensation level. The pre-to-post change was compared between the nicotine and placebo sessions.

Secondary outcomes

  1. Auditory selective attention after administration (Coordinate Response Measure percent correct), nicotine vs placeb

    Time frame: Up to 2 hours after gum administration

    Selective attention was assessed with the Coordinate Response Measure after gum administration and scored as the percentage of trials on which both the color and number were correctly identified; performance was compared between the nicotine and placebo sessions.

Other outcomes

  1. Tinnitus Handicap Inventory (THI) score

    Time frame: Baseline (first session, before administration)

    Pre-specified additional measure of tinnitus-related handicap.

  2. Tinnitus Functional Index (TFI) score

    Time frame: Baseline (first session, before administration)

    Pre-specified additional measure of tinnitus functional impact.

  3. Pure-tone audiometry (0.25-12 kHz)

    Time frame: Baseline (first session, before administration)

    Pre-specified additional measure of hearing thresholds.

Sponsors and collaborators

Lead sponsor

Xianhui Wang

Other

Registry information

Official study title

A Randomized, Double-Blind, Placebo-Controlled, Within-Subject Crossover Trial of a Single 4 mg Dose of Nicotine Polacrilex Gum on Psychoacoustic Tinnitus Loudness and Selective Attention in Non-Smoking Adults With Chronic Subjective Tinnitus

Important dates

Study start
2026
Primary completion
2026
Study completion
2026
First posted
Aug 19, 2026
Registry last updated
Aug 19, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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