Asthma | Anti-histamines and Methacholine Challenges.

Asthma research study

What is the primary objective of this study?

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.

Who is eligible to participate?

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

Which medical condition, disease, disorder, syndrome, illness, or injury is researched?


Study Interventions

Interventions can include giving participants drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available or noninvasive approaches such as surveys, education, and interviews.





Study Arms

Research studies and clinical trials typically have two or more research arms. An arm is a group of people who receive the same treatment in the study.

diphenhydramine50mg dose given as two 25mg capsules

cetirizine10mg dose given as 1 10mg capsule and 1 placebo capsule

desloratadine5mg dose given as 1 5mg capsule and 1 placebo capsule

placebogiven as 2 placebo capsules

Study Status


Start Date: November 2013

Completed Date: May 2014

Phase: Phase 4

Type: Interventional


Primary Outcome: change in methacholine pc20

Secondary Outcome:

Study sponsors, principal investigator, and references

Principal Investigator: Donald W Cockcroft, MD

Lead Sponsor: Don Cockcroft


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