Long duration of airway but not systemic effects of inhaled formoterol in asthmatic patients.
BACKGROUND
Formoterol is approved as asthma rescue medication in many countries. The exact duration of the airway vs. systemic effects of formoterol compared with another rescue medication, salbutamol, has not been evaluated.


OBJECTIVE
To assess the duration of airway bronchodilatory effects vs. systemic effects of inhaled formoterol and salbutamol in asthmatic patients.


METHODS
Twenty-six patients with stable and reversible asthma were given single doses of formoterol dry-powder inhaler (OxisTurbuhaler) 2x9 microg (lower dose; LD) and 6x9 microg (higher dose; HD), salbutamol (VentolinDiskhaler) 3x400 microg (LD) and 9x400 microg (HD), and placebo in a randomized, double-blind, crossover trial. Airway and systemic effects were assessed by forced expiratory volume in 1s (FEV1), serum potassium, blood pressure, corrected QT-interval (QTc), and palpitation and tremor scores. Time with clinically relevant bronchodilation (FEV1 increase 12%) without clinically relevant markers of systemic effects (serum potassium suppression 0.2 mmol/L, QTc-prolongation 20 ms, or heart rate increase 8 beats per minute) was evaluated.


RESULTS
Bronchodilation was maintained for 24h with both formoterol doses and for 7-11h with salbutamol. Maximum bronchodilation and systemic effects were similar after formoterol and salbutamol, except for statistically significantly larger maximum heart rate and palpitation and tremor scores after salbutamol. Systemic responses were similarly brief for formoterol and salbutamol (7 h).


CONCLUSIONS
The airway effects of inhaled formoterol are of long duration, whereas the systemic effects are of a similarly short duration as salbutamol. Thus, the time with clinically relevant bronchodilation without systemic effects is substantially longer after formoterol than after salbutamol.
Lötvall
Jan
J
Department of Internal Medicine/Respiratory Medicine and Allergology, Göteborg University, Sahlgrenska Hospital, Sweden. Jan.lotvall@gu.se
Ankerst
Jaro
J
D000280:Administration, Inhalation; D000328:Adult; D000368:Aged; D000420:Albuterol / Q000008:administration & dosage*; D001249:Asthma / Q000188:drug therapy* / Q000503:physiopathology; D001980:Bronchi / Q000187:drug effects / Q000503:physiopathology; D001993:Bronchodilator Agents / Q000008:administration & dosage*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D004983:Ethanolamines / Q000008:administration & dosage*; D005260:Female; D005541:Forced Expiratory Volume; D000068759:Formoterol Fumarate; D006801:Humans; D008297:Male; D008875:Middle Aged; D013997:Time Factors; D016896:Treatment Outcome
D001993:Bronchodilator Agents; D004983:Ethanolamines; D000420:Albuterol; D000068759:Formoterol Fumarate