ClUDo: The Clinical Utility of Capsaicin Dose Response Curves to Discriminate Cough Hyper-responsiveness

Not Applicable

Completed

• Conditions: Respiratory; Chronic cough

• Registration Number: ISRCTN23684347
• Lead Sponsor: niversity Hospital of South Manchester NHS Foundation Trust (UK)

Brief Summary

2017 Results article in https://www.ncbi.nlm.nih.gov/pubmed/27444176 results 2023 Results article in https://pubmed.ncbi.nlm.nih.gov/36736541/ (added 06/02/2023)

Detailed Description

Not available

Study Timeline

• Results First Posted: 1900-01-01
• Study Start: 2014-01-23
• Study Completion: 2014-08-04
• Last Update Posted: 20 February 2023

Recruitment & Eligibility

• Status: Completed
• Sex: All
• Target Recruitment: 200

Inclusion Criteria

Healthy volunteers:
1. Male and female aged over 18 years
2. Normal spirometry
3. No current or past history of chronic cough or respiratory disease
4. No current chronic pain, irritable bowel syndrome, psychiatric illness or chronic headaches

Chronic cough patients:
1. Male and female aged over 18 years
2. Diagnosis of chronic cough (defined as cough lasting more than 8 weeks)
3. Normal spirometry
4. Normal chest x-ray

Exclusion Criteria

1. Current smoker or ex-smoker with >20 pack year history, and >6 months abstinence
2. Upper respiratory tract infection within last 4 weeks
3. Use of angiotensin-converting-enzyme (ACE) inhibitors
4. Use of any centrally acting medications which may alter the cough reflex*
5. History of drug or alcohol abuse
6. Pregnancy or breastfeeding
7. Concomitant conditions which may alter cough reflex sensitivity e.g. diabetes mellitus, Parkinson?s disease, cerebrovascular disease.

Study & Design

• Study Type: Observational
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
Emax (maximum number of coughs provoked) and ED50 (capsaicin dose provoking half the Emax) will be measured to discriminate between male and female chronic cough patients and healthy controls to test the usefulness of the procedure as a clinical test. Measured at baseline only.

Secondary Outcome Measures

Name	Time	Method
Emax, ED50, cough severity visual analogue scales (VAS) and objective cough frequency will also be used to assess differences in male and female healthy volunteers and chronic cough patients. Measured at baseline only.