Anti-histamines and Methacholine Challenges.

Condition(s) targeted: Asthma

Intervention: Diphenhydramine (Drug); cetirizine (Drug); desloratadine (Drug); placebo (Drug)

Phase: Phase 4

Status: Completed

Sponsored by: Don Cockcroft

Official(s) and/or principal investigator(s):
Donald W Cockcroft, MD, Principal Investigator, Affiliation: University of Saskatchewan, Department of Medicine, Division of Respirology, Critical Care and Sleep Medicine

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.

Official title: The Effect of Antihistamines on Methacholine Challenge Testing in Asthma Patients

Study design: Allocation: Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Crossover Assignment, Masking: Double Blind (Subject, Investigator, Outcomes Assessor), Primary Purpose: Diagnostic

Primary outcome: change in methacholine pc20

Minimum age: 18 Years. Maximum age: N/A. Gender(s): Both.

Criteria:

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

University of Saskatchewan, Saskatoon, Saskatchewan S7N 0W8, Canada

Starting date: November 2013
Last updated: April 7, 2015