The Effect of Antihistamines on Methacholine Challenge Testing in Asthma Patients
Trial Snapshot
- Phase
- Phase 4
- Status
- Completed
- Sponsor
- Enrollment
- 12
- Locations
- 1
- Primary Endpoint
- change in methacholine pc20
Study Overview
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.
Study Design
- Study Type
- Interventional
- Allocation
- Randomized
- Intervention Model
- Crossover
- Primary Purpose
- Diagnostic
- Masking
- Triple (Participant, Investigator, Outcomes Assessor)
Eligibility Criteria
- Ages
- 18 Years to — (Adult, Older Adult)
- Sex
- All
- Accepts 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
Exclusion Criteria
- •pregnant or breastfeeding females
- •unable to withhold antihistamines, anticholinergics, long acting bronchodilators and combination therapies
Arms & Interventions
diphenhydramine
50mg dose given as two 25mg capsules
Intervention: Diphenhydramine (Drug)
cetirizine
10mg dose given as 1 10mg capsule and 1 placebo capsule
Intervention: cetirizine (Drug)
desloratadine
5mg dose given as 1 5mg capsule and 1 placebo capsule
Intervention: desloratadine (Drug)
placebo
given as 2 placebo capsules
Intervention: placebo (Drug)
Outcomes
Primary Outcomes
change in methacholine pc20
Time Frame: change from baseline (pre dose) at 2 hours (post dose)
Secondary Outcomes
No secondary outcomes reported
Investigators
Don Cockcroft
Professor
University of Saskatchewan