Influence of beclomethasone and salmeterol on the perception of methacholine-induced bronchoconstriction.
BACKGROUND
Patient evaluation of asthma severity and medication needs is mostly based on respiratory symptoms and may be influenced by changes in perception of bronchoconstriction-induced sensations. However, the influence of asthma medication on the ability to perceive symptoms is still to be documented. This study evaluated the effects of short-term and regular use of salmeterol on the perception of methacholine-induced bronchoconstriction (MIB) in subjects with mild asthma, using inhaled salbutamol on an "as required" basis (n=15), and in subjects with moderate asthma, using daily inhaled beclomethasone (mean daily dose, 640 microg; n=15) in addition to salbutamol to control their asthma.


METHODS
Methacholine challenges (MC) were performed at entry into the study, and then before, 1, and 12 h following inhalation of 50 microg of salmeterol or a placebo, after a 15-day baseline period; and after 4 weeks of twice daily use of those treatments. The measurements were then repeated with the alternate treatment after a 15-day washout period. Finally, a last MC was performed after another 15-day washout period. For each MC, the perception score of bronchoconstriction-associated breathlessness at 20% fall in FEV1 (PS20) was evaluated on a modified Borg scale from 0 to 10.


RESULTS
Subjects using regular beclomethasone had a higher baseline PS20 than those using only salbutamol (means: 3.06 0.06 and 2.01+/-0.07, p=0.0001). Short- and long-term use of salmeterol did not change significantly the PS20 compared with placebo (p>0.05) in either group (with or without corticosteroid). Although there were some intraindividual variations, mean PS20 did not vary significantly throughout the study.


CONCLUSIONS
These observations show that the perception of bronchoconstriction-associated breathlessness is not influenced by regular use of salmeterol. Patients using inhaled corticosteroids show a greater perception of MIB.
Boulet
L P
LP
Le Centre québécois d'excellence en santé respiratoire, Unité de Recherche, Centre de Pneumologie de l'Hôpital Laval, Université Laval, Sainte-Foy, Québec, Canada.
Turcotte
H
H
Cartier
A
A
Milot
J
J
Côté
J
J
Malo
J L
JL
Laviolette
M
M
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 / Q000503:physiopathology; D001507:Beclomethasone / Q000008:administration & dosage / Q000627:therapeutic use*; D016084:Bronchoconstriction / Q000187:drug effects*; D016085:Bronchoconstrictor Agents; D001993:Bronchodilator Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D005500:Follow-Up Studies; D005541:Forced Expiratory Volume / Q000187:drug effects; D005938:Glucocorticoids / Q000008:administration & dosage / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D016210:Methacholine Chloride; D008875:Middle Aged; D010465:Perception; D000068299:Salmeterol Xinafoate; D012720:Severity of Illness Index; D016896:Treatment Outcome
D016085:Bronchoconstrictor Agents; D001993:Bronchodilator Agents; D005938:Glucocorticoids; D016210:Methacholine Chloride; D000068299:Salmeterol Xinafoate; D001507:Beclomethasone; D000420:Albuterol