Protective effects of different doses of inhaled fenoterol on methacholine-induced bronchoconstriction in asthmatic children

Protective effects of different doses of inhaled fenoterol on methacholine-induced bronchoconstriction in asthmatic children

Author Gomez, Irma Douglas Autor UNIFESP Google Scholar
Silva, Marilia De Dirceu Autor UNIFESP Google Scholar
Bueno, Maria Poliana Autor UNIFESP Google Scholar
Solé, Dirceu Autor UNIFESP Google Scholar
Naspitz, Charles Kirov Autor UNIFESP Google Scholar
Institution Universidade Federal de São Paulo (UNIFESP)
Abstract OBJECTIVE: To evaluate the protective effect of different doses of inhaled fenoterol (F) on bronchoconstriction induced by methacholine (M).DESIGN: randomized double-blind study.SETTING: Referrence center.PARTICIPANTS: 9 children (aged from 7 to 15 years old), with mild or moderate asthma and allergic to D. pteronyssinus.INTERVENTION: On the first day, the M concentration necessary to induce a 20% fall in the forced expiratory volume in the first second (FEV1; PC20FEV1) was determined using closed circuit inhalation (De Vilbiss 646). On subsequent days, the children inhaled a dose of F (25 or 50 or 100 or 200 µg) through the same circuit and, after 15 minutes the FEV1 was measured, becoming the basal value. Bronchoprovocation was then initiated using the concentration prior to the PC20FEV1 of the first day and continuing until there was a 20% fall in the FEV1. This concentration was the new PC20FEV1.RESULTS: F in a dose of 25 µg protected 2 of the 9 children, in a dose of 50 mg protected 4 of the 9 and in doses of 100 and 200 µg protected all children. We did not observe any relationship between the magnitude of the bronchodilation and bronchoprotection induced by the inhalation of F. CONCLUSIONS: Our results suggest that a dose of 100 µg of F is capable of inducing bronchoprotection in children with mild/moderate asthma.

OBJETIVOS: Avaliar o efeito protetor de diferentes doses de fenoterol (F) inalado sobre a broncoconstrição induzida por metacolina (M). TIPO DE ESTUDO: estudo duplo-cego e randomizado. LOCAL: Centro de referência. PARTICIPANTES: Nove crianças (7 a 15 anos) com asma leve ou moderada, alérgicas ao D. pteronyssinus. INTERVENÇÃO: As doses de F (25 ou 50 ou 100 ou 200 µg) foram administradas por inalação com circuito fechado (De Vilbiss 646). No primeiro dia determinou-se a concentração de M capaz de induzir queda de 20% nos valores de VEF1 (CP20VEF1). Nos dias subseqüentes, inalavam a dose de F pelo mesmo circuito medindo o VEF1 15 minutos após (referência). A seguir iniciavam a broncoprovocação pela concentração anterior à da CP20VEF1 do primeiro dia e prosseguiam até que houvesse queda de 20% no valor do VEF1 para a determinação do novo CP20VEF1. RESULTADOS: O F inalado na dose de 25 µg protegeu 2/9 crianças e na de 50 µg houve proteção de 4/9 crianças. Todos os pacientes foram protegidos com as doses de 100 e 200 µg. Não observamos relação entre a magnitude da broncodilatação e broncoproteção induzidas pela inalação do F. CONCLUSÕES: Nossos resultados sugerem que a dose de 100 µg de F é protetora da broncoconstrição em crianças com asma leve/moderada.
Keywords Asthma
Children
Bronchial hyperreactivity
Beta agonists
Fenoterol
Methacholine
Language English
Date 1998-11-01
Published in São Paulo Medical Journal. Associação Paulista de Medicina - APM, v. 116, n. 6, p. 1834-1837, 1998.
ISSN 1516-3180 (Sherpa/Romeo)
Publisher Associação Paulista de Medicina - APM
Extent 1834-1837
Origin http://dx.doi.org/10.1590/S1516-31801998000600002
Access rights Open access Open Access
Type Article
SciELO ID S1516-31801998000600002 (statistics in SciELO)
URI http://repositorio.unifesp.br/handle/11600/689

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