Asthma
Conditions
Keywords
airway hyperresponsiveness
Brief summary
The asthmatic airway is identified and studied using inhaled agents such as histamine and methacholine. The use of antihistamines prior to the test will inhibit the test result if histamine is used to cause airway constriction. If using methacholine, this may also be true depending on whether old (e.g. benadryl) or new (e.g. desloratadine) antihistamines are used. This study will look at the effect of old and new antihistamines on inhaled methacholine challenge response in individuals with mild asthma.
Interventions
DRUGDiphenhydramine
DRUGcetirizine
DRUGdesloratadine
DRUGplacebo
Sponsors
Don Cockcroft
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
DIAGNOSTIC
Masking
TRIPLE (Subject, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Baseline forced expiratory volume in 1s (FEV1) of 70% or more of predicted * Methacholine provocative concentration causing a 20% fall in FEV1 16mg/ml or less * No respiratory infection or change in allergen exposure for 4 weeks prior to screening and throughout the study * No significant medical co-morbidities * allergy
Exclusion criteria
* pregnant or breastfeeding females * unable to withhold antihistamines, anticholinergics, long acting bronchodilators and combination therapies
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| change in methacholine pc20 | change from baseline (pre dose) at 2 hours (post dose) |
Countries
Canada
Outcome results
None listed