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Canadian Respiratory Journal
Volume 10, Issue 1, Pages 23-26
Original Article

Formoterol Thrice Weekly Does Not Result in the Development of Tolerance to Bronchoprotection

Beth E Davis, John K Reid, and Donald W Cockcroft

Division of Respiratory Medicine, Department of Medicine, Royal University Hospital, Saskatoon, Saskatchewan, Canada

Copyright © 2003 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


BACKGROUND: Loss of bronchoprotection routinely follows regular treatment with beta2-agonists. There are no data on the effects on bronchoprotection for thrice weekly use of a beta2-agonist.

METHODS: A double-blind, randomized, placebo controlled crossover trial was conducted to investigate the effects of thrice weekly administration of 12 μg of formoterol versus placebo on bronchoprotection against methacholine. As an expected positive control, formoterol 12 μg once daily was also evaluated.

RESULTS: There was no significant difference versus placebo in the bronchoprotective effects of 12 μg of formoterol administered on day 8, following daily treatment for seven days or treatment every other day (analysis of variance P=0.34). However, a nonsignificant trend towards lower concentration of methacholine that caused a 20% fall in forced expiratory volume in 1 s developed only following the daily formoterol dosing.

CONCLUSIONS: Thrice weekly dosing does not result in the development of tolerance to bronchoprotection against the direct acting stimulus methacholine.