title: The effect of inhaled salmeterol on methacholine responsiveness in subjects with asthma up to 12 hours.
abstract: The duration of the protective effect of 50 and 100 micrograms of inhaled salmeterol against methacholine-induced bronchoconstriction was compared with that of 200 micrograms of inhaled salbutamol in 12 patients with asthma with a baseline FEV1 of at least 70% and a provocative concentration of inhaled methacholine causing a 20% fall in FEV1 (PC20) greater than or equal to 8 mg/ml. The study was placebo controlled, double blind, randomized, and crossover. The bronchodilating effect was no longer significant 4 hours after inhalation of salbutamol, whereas the effect was still present 12 hours after administration of 50 and 100 micrograms of salmeterol. All active treatments caused PC20 to increase at 1 hour (p less than 0.05). PC20 (milligrams per milliliter) thus reached 3.7 +/- 0.8 after placebo, 13.8 +/- 3.0 after 50 micrograms of salmeterol, 23.2 +/- 4.7 after 100 micrograms of salmeterol, and 13.9 +/- 3.4 after 200 micrograms of salbutamol. The protective effect of 200 micrograms of salbutamol was no longer significant at 4 hours, whereas both doses of salmeterol protected against methacholine challenge up to 12 hours after inhalation (p less than 0.01). An increased incidence of tremor (2/12) and palpitations (2/12) was recorded after inhalation of 100 micrograms of salmeterol. We conclude that inhalation of 50 or 100 micrograms of salmeterol causes a long-lasting bronchodilatation and protects against methacholine-induced bronchoconstriction for at least 12 hours.
authors.affiliation: Department of Respiratory Diseases, University Hospital, Ghent, Belgium.
authors.forename: E Y
authors.initials: EY
authors.lastname: Derom
authors.forename: R A
authors.initials: RA
authors.lastname: Pauwels
authors.forename: M E
authors.initials: ME
authors.lastname: Van der Straeten
mesh_terms: D000280:Administration, Inhalation; D000293:Adolescent; D000328:Adult; D000420:Albuterol / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000627:therapeutic use; D001249:Asthma / Q000175:diagnosis / Q000188:drug therapy*; D001985:Bronchial Provocation Tests; D001993:Bronchodilator Agents / Q000008:administration & dosage* / Q000627:therapeutic use; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008297:Male; D008688:Methacholine Compounds; D000068299:Salmeterol Xinafoate
chemical_list: D001993:Bronchodilator Agents; D008688:Methacholine Compounds; D000068299:Salmeterol Xinafoate; D000420:Albuterol