The bronchial response to mannitol is attenuated by a previous methacholine test: but not vice versa.
OBJECTIVE
To examine the airway response to inhaled mannitol performed before or after a methacholine challenge test in a group of asthmatics with different levels of disease.


METHODS
A total of 48 asthmatics, 18-73 years of age, were included in the study. Two pairs of challenges were performed in a random order on two separate days > or =24 h apart: either with mannitol performed first on day one, followed > or =1 h by methacholine, and methacholine as the first on day two, followed > or =1 h by mannitol or vice versa. A questionnaire-based interview was performed and lung function, exhaled nitric oxide, skin prick test, and blood eosinophil count were measured.


RESULTS
A total of 44% of the asthmatics used inhaled corticosteroids and 48% were atopic. The airway response to mannitol was attenuated when mannitol was given after methacholine, compared with the response to mannitol when it was given first [log response dose ratio (RDR): 1.42 vs. 1.60 (P=0.004)], whereas the response to methacholine was unchanged in the opposite test order [log RDR: 0.81 vs. 0.96 (P=0.102)].


CONCLUSIONS
Bronchial challenges with inhaled mannitol and methacholine may be performed on the same day but provocation with mannitol should be performed before methacholine.
Gade
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E
Department of Respiratory Medicine, Copenhagen University Hospital, Bispebjerg Hospital, Copenhagen, Denmark.
Thomsen
S F
SF
Porsbjerg
C
C
Backer
V
V
D000280:Administration, Inhalation; D000293:Adolescent; D000328:Adult; D000368:Aged; D001249:Asthma / Q000175:diagnosis* / Q000276:immunology / Q000503:physiopathology; D001980:Bronchi / Q000187:drug effects* / Q000276:immunology; D016535:Bronchial Hyperreactivity / Q000175:diagnosis* / Q000276:immunology / Q000503:physiopathology; D001985:Bronchial Provocation Tests / Q000379:methods*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D007407:Interviews as Topic; D008297:Male; D008353:Mannitol / Q000008:administration & dosage / Q000009:adverse effects* / Q000276:immunology; D016210:Methacholine Chloride / Q000276:immunology; D008875:Middle Aged; D011795:Surveys and Questionnaires; D055815:Young Adult
D016210:Methacholine Chloride; D008353:Mannitol