Anti-histamines and Methacholine Challenges.

Don Cockcroft

Status and phase: Completed; Phase 4

Conditions: Asthma

Treatments: Drug: Diphenhydramine; Drug: cetirizine; Drug: placebo; Drug: desloratadine

Study type: Interventional

Funder types: Other

Identifiers

NCT01985789

PHPY2013/14

Details and patient eligibility

About

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.

Enrollment: 12 patients

Sex: All

Ages: 18+ years old

Volunteers: No Healthy Volunteers

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

Trial design

Primary purpose: Diagnostic

Allocation: Randomized

Interventional model: Crossover Assignment

Masking: Triple Blind

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12 participants in 4 patient groups, including a placebo group

diphenhydramine

Active Comparator group

Description:

50mg dose given as two 25mg capsules

Treatment:

Drug: Diphenhydramine

cetirizine

Active Comparator group

Description:

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

Treatment:

Drug: cetirizine

desloratadine

Active Comparator group

Description:

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

Treatment:

Drug: desloratadine

placebo

Placebo Comparator group

Description:

given as 2 placebo capsules

Treatment:

Drug: placebo