Long-Acting Beta Agonists: Salmeterol and Formeterol

Salmeterol and Formeterol
Two long-acting ß 2 -adrenergic agonists (LABAs), salmeterol and formoterol, have been demonstrated to be safe and effective agents in children, both in terms of bronchodilation and prevention of exercise-induced bronchospasm. Their onsets of action differ, with formoterol having an onset similar to albuterol (3 minutes), while salmeterol has a slower onset of action (10–20 minutes). Following a single-dose administration, both agents demonstrate durations of action up to 12 hours. Following regular twice-daily administration, bronchodilation remains effective; however, a level of tolerance (or tachyphylaxis) (more…)

Long Acting Agonist (ß2) Therapy to Inhaled Corticosteroids in Persistent Asthma?

long acting agonist
Current internationally recognized guidelines indicate that symptomatic asthmatics using a low to medium inhaled corticosteroid dose (400–800 µg/day of beclomethasone or equivalent) alone should preferentially be commenced on a long-acting agonist ß2 prior to an leukotriene receptor antagonists LTRA (British guideline on the management of asthma 2003; GINA Workshop Report 2004). However, two recent large trials have performed head to-head comparisons of add-on long-acting ß2 agonist versus LTRA as therapeutic adjuncts to inhaled corticosteroids, using exacerbation frequency (rather than lung function and symptoms) as the primary end point. (more…)

Long Acting Beta-Agonist Bronchodilator Tolerance

Regular use of ß-agonists has been known to lead to tolerance to their bronchodilator effects. It is not known how quickly tolerance develops or how long it lasts after stopping ß-agonist therapy.

Bronchodilator tolerance occurs after even a single dose and reaches a maximum after 1 week of regular formoterol. Sensitivity recovers 3 days after stopping treatment. (more…)