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Effect of acetazolamide and amiloride against sodium metabisulphite-induced bronchoconstriction in mild asthma.
Thorax. 1994 Nov; 49(11):1096-8.T

Abstract

BACKGROUND

Inhaled frusemide but not bumetanide, another loop diuretic, reduces bronchial responsiveness to sodium metabisulphite (MBS). To investigate whether the effect of frusemide could be mediated through mechanisms other than Na+/K+/Cl- cotransporter inhibition, the effects of amiloride--an inhibitor of sodium channels in the airway epithelium--and of acetazolamide--a specific inhibitor of carbonic anhydrase--against MBS challenge were studied.

METHODS

In two separate randomised double blind placebo controlled studies, 10 subjects with mild asthma attended on four separate occasions to inhale 7.5 mg amiloride or matched placebo, and 500 mg acetazolamide or placebo, immediately before MBS challenge. The concentration of MBS required to cause a 20% fall in baseline FEV1 (PC20) was measured.

RESULTS

Amiloride and acetazolamide had no effect on baseline FEV1. Amiloride had no effect against MBS challenge, but acetazolamide increased -log PC20 from a mean (SE) of 0.75 (0.09) to 0.98 (0.06) representing a 0.77 (0.24) doubling dose increase.

CONCLUSIONS

These results suggest that carbonic anhydrase activity in the airways, but not sodium flux, modulates bronchial responsiveness to MBS challenge. The action of frusemide is not likely to involve inhibition of carbonic anhydrase activity.

Authors+Show Affiliations

Department of Thoracic Medicine, National Heart and Lung Institute, Royal Brompton Hospital, London, UK.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Clinical Trial
Journal Article
Randomized Controlled Trial

Language

eng

PubMed ID

7831623

Citation

O'Connor, B J., et al. "Effect of Acetazolamide and Amiloride Against Sodium Metabisulphite-induced Bronchoconstriction in Mild Asthma." Thorax, vol. 49, no. 11, 1994, pp. 1096-8.
O'Connor BJ, Yeo CT, Chen-Worsdell YM, et al. Effect of acetazolamide and amiloride against sodium metabisulphite-induced bronchoconstriction in mild asthma. Thorax. 1994;49(11):1096-8.
O'Connor, B. J., Yeo, C. T., Chen-Worsdell, Y. M., Barnes, P. J., & Chung, K. F. (1994). Effect of acetazolamide and amiloride against sodium metabisulphite-induced bronchoconstriction in mild asthma. Thorax, 49(11), 1096-8.
O'Connor BJ, et al. Effect of Acetazolamide and Amiloride Against Sodium Metabisulphite-induced Bronchoconstriction in Mild Asthma. Thorax. 1994;49(11):1096-8. PubMed PMID: 7831623.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Effect of acetazolamide and amiloride against sodium metabisulphite-induced bronchoconstriction in mild asthma. AU - O'Connor,B J, AU - Yeo,C T, AU - Chen-Worsdell,Y M, AU - Barnes,P J, AU - Chung,K F, PY - 1994/11/1/pubmed PY - 1994/11/1/medline PY - 1994/11/1/entrez SP - 1096 EP - 8 JF - Thorax JO - Thorax VL - 49 IS - 11 N2 - BACKGROUND: Inhaled frusemide but not bumetanide, another loop diuretic, reduces bronchial responsiveness to sodium metabisulphite (MBS). To investigate whether the effect of frusemide could be mediated through mechanisms other than Na+/K+/Cl- cotransporter inhibition, the effects of amiloride--an inhibitor of sodium channels in the airway epithelium--and of acetazolamide--a specific inhibitor of carbonic anhydrase--against MBS challenge were studied. METHODS: In two separate randomised double blind placebo controlled studies, 10 subjects with mild asthma attended on four separate occasions to inhale 7.5 mg amiloride or matched placebo, and 500 mg acetazolamide or placebo, immediately before MBS challenge. The concentration of MBS required to cause a 20% fall in baseline FEV1 (PC20) was measured. RESULTS: Amiloride and acetazolamide had no effect on baseline FEV1. Amiloride had no effect against MBS challenge, but acetazolamide increased -log PC20 from a mean (SE) of 0.75 (0.09) to 0.98 (0.06) representing a 0.77 (0.24) doubling dose increase. CONCLUSIONS: These results suggest that carbonic anhydrase activity in the airways, but not sodium flux, modulates bronchial responsiveness to MBS challenge. The action of frusemide is not likely to involve inhibition of carbonic anhydrase activity. SN - 0040-6376 UR - https://www.unboundmedicine.com/medline/citation/7831623/Effect_of_acetazolamide_and_amiloride_against_sodium_metabisulphite_induced_bronchoconstriction_in_mild_asthma_ L2 - https://thorax.bmj.com/lookup/pmidlookup?view=long&pmid=7831623 DB - PRIME DP - Unbound Medicine ER -