Article,
Inhaled dry-powder formoterol and salmeterol in asthmatic patients: onset of action, duration of effect and potency
EUROPEAN RESPIRATORY JOURNAL, 10 (11): 2484-2489 (November 1997)
DOI: {10.1183/09031936.97.10112489}
Abstract
Salmeterol and formoterol are two long-acting Pz-agonists for
inhalation, currently being used in clinical practice, The aim of the
present study was to investigate the onset of action, duration of effect
and potency of these two beta(2)-agonists in asthmatic patients,
Patients (n=28) were included on the basis of salbutamol stepwise
reversibility (100, 100 and 200 mu g, given cumulatively; total
reversibility greater than or equal to 15\%). In a double-blind
placebo-controlled crossover study, the bronchodilating properties of
formoterol 6, 12 and 24 mu g were compared with the effects of
salmeterol 50 mu g.
Formoterol was given via Turbuhaler(R) and salmeterol via Diskhaler(R)
and forced expiratory volume in one second (FEV1) was monitored during
12 h. Formoterol at all doses had a more rapid onset than salmeterol as
judged from bronchodilation at 3 min after the dose, Formoterol at all
doses had a similar duration of effect to salmeterol 50 mu g, as judged
from bronchodilation at 12 h after dose administration, When the
relative potency of the two drugs was compared. salmeterol 50 mu g was
estimated to correspond to formoterol 9 mu g (95\% confidence interval:
3-19 mu g),
We confirm that formoterol and salmeterol are both long-acting
beta(2)-agonists, but with some differences in effect profile. We
confirm the more rapid onset of action of formoterol compared with
salmeterol, and furthermore, no difference in duration of effect is
evident.
