Chronic Cough, Bronchiectasis
Conditions
Keywords
Adenosine triphosphate, Capsaicin, cough provocation test
Brief summary
This is a randomized, cross-over, single-blind trial. Eligible patients will be randomly assigned to undergo either capsaicin or adenosine triphosphate (ATP) cough provocation test, followed by a washout period of 2 to 14 days. Participants will be crossed-over to undergo another cough provocation test. Patient would be under observation in the out-patient clinics for \ 2 hours following the cough provocation tests in case of severe adverse events.
Detailed description
This is a randomized, cross-over, single-blind trial. After verification of the entry criteria, eligible patients will be, based on the randomization codes, randomly assigned to undergo either capsaicin or ATP cough provocation test (the participants will inhale capasaicin or ATP incremental concentration to induce cough, meanwhile the number of coughs and adverse events will be recorded in each concentration during the first 30 seconds), followed by a washout period of 2 to 14 days (no major changes in the use of concomitant medications are allowed,especially the medcines which are not allowed before test ). Participants will be crossed-over to undergo another cough provocation test. Patient would be under observation in the out-patient clinics for \ 2 hours following the cough provocation tests in case of severe adverse events. Twenty four hours after each test, a follow-up telephone visit will be scheduled for all patients to record any response which may be related to the test.
Interventions
DIAGNOSTIC_TESTAdenosine Triphosphate
Adenosine Triphosphate aerosol
DIAGNOSTIC_TESTcapsaicin
capsaicin aerosol
Sponsors
Guangzhou Institute of Respiratory Disease
Study design
Observational model
CASE_CONTROL
Time perspective
CROSS_SECTIONAL
Eligibility
Sex/Gender
ALL
Age
18 Years to 60 Years
Healthy volunteers
Yes
Inclusion criteria
* Out-patients of either gender, ex- or never-smokers, aged between 18 and 60 years * Cough symptoms lasting for more than 8 weeks * Remaining free of acute upper respiratory tract infection for at least 4 weeks * Agreed to participate in the trial and signed informed consent.
Exclusion criteria
* Patients with serious systemic diseases (such as malignant tumors), bullae, severe uncontrolled asthma, and a history of major hemoptysis * Systemic antibiotic use (except for maintenance low-dose macrolides) within 4 weeks * Pregnancy or lactation * Any known history of sensitivity to ATP or capsaicin * Poor understanding of the test procedure * Diagnosed with cough variant asthma or Eosinophilic bronchitis
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| C5 (Provocant concentration eliciting at least 5 coughs) | 18 months | Provocant concentration eliciting at least 5 coughs |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Emax (effective concentration of provocant eliciting maximal cough count) | 18 months | effective concentration of provocant eliciting maximal cough count |
| potency ratio | 18 months | ATP/capsaicin potency ratio |
| ED50 (half maximal effective Dose) | 18 months | 50% effective dose of provocant |
| The incidence of adverse events (i.e. dry throat , pharyngeal itching) | 18 months | adverse events such as dry throat , pharyngeal itching, wheeze or dyspnea according to the subject's reporting to record the rate of the incidence and the severity (the aboved-mentioned VAS score would be applied) |
| Cough dose ratio (CDR) | 18 months | the ratio of cough count and dose/concentration |
| Difference in cough VAS score (a 10-point likert scale for assessing the global severity of cough, no subscale was applied) | 18 months | The difference between pre- and post-challenge cough VAS scores |
Countries
China
Contacts
Primary ContactWei-jie Guan, MD
Backup ContactJing jing Yuan, Msc
Outcome results
None listed