Formoterol, a new inhaled beta-2 adrenergic agonist, has a longer blocking effect than albuterol on hyperventilation-induced bronchoconstriction.
The duration of effect of inhaled formoterol (24 micrograms) was compared with that of a placebo and that of inhaled albuterol (200 micrograms) in 12 adult asthmatic subjects who underwent hyperventilation tests with cold dry air (-20 degrees C) on 4 study days. On the control day, they were subjected to four hyperventilation tests to ensure functional stability. On the 3 remaining days, after a first hyperventilation test, they inhaled placebo, albuterol, or formoterol in randomized, double-blind fashion. The hyperventilation test was repeated 1, 4, and 8 h and, if the blocking effect was still present, 12 and 24 h after the drug had been administered. The dose of hyperventilation of cold air causing a 20% fall in FEV1 (PD20) was interpolated on the dose-response curve. The magnitude of the blocking effect at each time interval on each study day was assessed by comparing the changes in PD20 from baseline with the within-day variability of PD20 (standardized change in PD20). The acute bronchodilator effect was not significantly different as assessed 15 min (21 +/- 14% for albuterol and 18 +/- 18% for formoterol) and 1 h (20 +/- 13% for albuterol and 18 +/- 17% for formoterol) after administering the medication. The duration of the blocking effect, defined as the return to 2 SD from the standardized change in PD20, was significantly more prolonged for formoterol (8.0 +/- 3.4 h) than for albuterol (3.0 +/- 1.7 h) (t = 4.2, p less than 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)
Malo
J L
JL
Department of Chest Medicine, Hôpital du Sacré-Coeur, Montreal, Canada.
Cartier
A
A
Trudeau
C
C
Ghezzo
H
H
Gontovnick
L
L
D000280:Administration, Inhalation; D000318:Adrenergic beta-Agonists / Q000627:therapeutic use*; D000328:Adult; D000368:Aged; D000420:Albuterol / Q000008:administration & dosage* / Q000627:therapeutic use; D001249:Asthma / Q000150:complications / Q000188:drug therapy* / Q000503:physiopathology; D016084:Bronchoconstriction / Q000187:drug effects*; D003080:Cold Temperature; D004311:Double-Blind Method; D004983:Ethanolamines / Q000008:administration & dosage* / Q000627:therapeutic use; D005260:Female; D005541:Forced Expiratory Volume; D000068759:Formoterol Fumarate; D006801:Humans; D006985:Hyperventilation / Q000150:complications / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D014797:Vital Capacity
D000318:Adrenergic beta-Agonists; D004983:Ethanolamines; D000420:Albuterol; D000068759:Formoterol Fumarate