Cough Desensitization Therapy: Pilot 2 — CDTPilot2  

Cough Clinical Trial

Official title: Cough Desensitization Therapy for Cough Hypersensitivity Syndrome: Pilot 2

Status Completed

Clinical Trial Summary

The purpose of this study is to investigate a modified behavioral treatment for chronic cough due to cough hypersensitivity syndrome (CHS). This type of CC is a non-productive cough that is due, in part, to over-expression of transient receptor potential vanilliod (TRPV) receptors in the airway epithelium, which contribute to a dry cough elicited by typically non-tussive stimuli (e.g., cold air, smells) or by low doses of tussive stimuli (e.g., smoke). Currently available treatment options are limited to neuromodulator medications (e.g., gabapentin, amytriptiline) and behavioral cough suppression therapy (BCST), neither of which is 100% effective. The primary component of BCST is teaching patients to suppress their cough in the presence of an urge-to-cough. Studies have confirmed a reduction in cough sensitivity (as tested with inhaled capsaicin) following 1-4 weeks of successful cough suppression. However, patients with severe CHS are not able to suppress their cough in the presence of uncontrollable environmental stimuli and, hence, do not respond well to the therapy. The purpose of this study is to determine the potential of treating CHS by implementing BCST while stimulating cough with progressive concentrations of inhaled diluted aerosolized capsaicin. The investigators hypothesize this treatment will result in a reduction in cough-reflex sensitivity, cough-related quality of life, and cough frequency.

Clinical Trial Description

The study will be a randomized, placebo-controlled, blinded study. It will take place in three phases, across 10 weeks.

WEEK 1: BASELINE TESTING AND TRAINING (approximate time = 1 hour).

Cough sensitivity testing: Standardized procedures that have been established and approved by the FDA will be used to determine cough sensitivity. Participants will inhale capsaicin vapor (a known cough stimulant) through a nebulizer with dosimeter, that delivers a specific dose of capsaicin in a mist form. They will inhale doubling doses of capsaicin mist from .49 micromolar to 1000 micromolar. The testing will be stopped when the investigators find the dose that causes five coughs or after giving the 1000 micromolar dose, whichever comes first. This testing will take approximately 30 minutes.

Urge-to-cough (UTC) testing: Participants be asked to report their UTC on a scale from 0 (no UTC) to 10 (maximum UTC) after each mist of capsaicin and after being presented with the following stimulants/tasks that cause some people to cough: perfume, bleach, vinegar, wood chips, laundry soap, cleaning wipe, deep and fast breath through the mouth, sustained voicing, reading a 55 word passage, and yelling a short phrase). This testing will take about 10 minutes.

Cough-related quality of life: Participants will complete the Leicester Cough Questionnaire which is a 23-item validated questionnaire designed to measure cough-related quality of life. It will take about 5 minutes.

Visual analogue cough severity (VAS): Participants will rate their cough severity on a visual analogue scale by placing a tick mark on a 100 mm line where 0 mm indicates "no cough" and 100 mm indicates "worst possible cough".

WEEKS 2-7: TREATMENT. Participants will attend treatment sessions twice per week for up to six weeks. Participants will use the breathing strategies following inhalation of either the active substance (experimental condition) or repeated exposures to an inactive substance (placebo condition). Participants will do this no more than twelve times per session. Each session will take 45-60 minutes. If a participant misses a treatment session, the investigators will attempt to re-schedule that session. Each participant must complete at least 10 treatment sessions to remain in the study.

WEEKS 8 AND 10: POST-TREATMENT TESTING. Outcome measures, as in the baseline phase, will be taken at one-week and three-weeks post-treatment. The LCQ will be measured again at three-months post-treatment. ;

Related Conditions & MeSH terms

• Cough

• NCT number: NCT05226299
• Study type: Interventional
• Source: University of Montana
• Status: Completed
• Phase: Phase 1
• Start date: May 1, 2021
• Completion date: August 30, 2022