Subjects with mild asthma, i.e. steroid naive Respiratory Asthma
Conditions
Interventions
This is an eight-visit randomised, single-blind, placebo-controlled, two-way cross-over study comparing cough responses to inhaled capsaicin in allergic asthma patients during and 24 hours after expos
Sponsors
University Hospital of South Manchester (UK)
Eligibility
Sex/Gender
All
Inclusion criteria
Inclusion criteria: 1. Aged =18 2. Has a diagnosis of atopic asthma (based on at least one positive skin prick test) 3. The subject is treated with: Short acting Beta 2 Agonist PRN 4. Controlled or has partial asthma control according to GINA classification 5. The subject has an early and late response to an inhaled allergen to which they are sensitised (assess after visit 2)
Exclusion criteria
Exclusion criteria: 1. Subjects who have previously coughed less than a total of 4 coughs in one dose at the ED50 dose of capsaicin inhalation (assess after visit 1) 2. Subjects who bronchoconstrict by more than 10% at the end of the full dose capsaicin cough challenge (assess after visit 1) 3. Subjects who do not display evidence of airway hyperresponsiveness (PC20>16mg/ml) (assess after visit 1) 4. Symptoms of upper respiratory tract infection (URTI) in the last 1 month which have not resolved 5. Lower respiratory tract infection or pneumonia in the last 6 weeks 6. Current smoker or exsmoker with =10 pack year smoking history and abstinence of =6 months 7. Asthma exacerbation in the previous month requiring an increase or start of an ICS or OCS 7. Asthma medication which include theophylline or anticholinergic drugs 8. Subject has changed asthma medication within the past 4 weeks prior to screening 9. A previous asthma exacerbation requiring Intensive Care Unit (ICU) admission 10. Significant other primary pulmonary disorders, in particular: pulmonary embolism, pulmonary hypertension, interstitial lung disease, lung cancer, cystic fibrosis, emphysema or bronchiectasis 11. Pregnancy or breastfeeding 12. Use of ACE inhibitors 13. Any centrally acting medication which in the view of the investigator could alter the sensitivity of the cough reflex* 14. History of psychiatric illness, drug or alcohol abuse which may interfere with participation in the trial *Any participant who is taking tricyclic antidepressants, pregabalin, gabapentin or opioids will not be eligible to take part in this study unless they are willing and medically able to withdraw from such medication for the duration of the study. The reason for this is that centrally acting medications may alter the sensitivity of the cough reflex.
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| The number of coughs evoked by an ED50 dose of capsaicin 30 minutes and 24 hours after an allergen challenge compared with saline inhalation | — |
Secondary
| Measure | Time frame |
|---|---|
| 1. 24-hour cough counts during allergen challenge compared with diluent 2. Correlations between changes in FEV1 and capsaicin cough responses 3. Correlations between changes in inflammation and capsaicin cough responses 4. Sputum cellular profile before and after allergen challenge compared with diluent 5. Changes in FEV1 before, during and after allergen challenge compared with diluent | — |
Countries
Canada, United Kingdom
Contacts
Public ContactImran Satia
Outcome results
None listed