Short acting bronchodilators include albuterol, a ß2-agonist, and short-acting anticholinergics ipratropium (Atrovent) producing bronchodilation for 4-6 hours.
Long-acting ß2-agonists formoterol (Foradil) and salmeterol (Serevent) have a duration of 12 or more hours.
Long acting beta agonist stimulates sympathetic control.
Salmeterol is currently available as a metered-dose inhaler (MDI) or a proprietary disk inhaler that releases a powdered form of the drug.
Formoterol has a faster onset of action than salmeterol as a result of a lower lipophilicity.
Formoterol is more potent than salmeterol—a 12 µg dose of formoterol has been demonstrated to be equivalent to a 50 µg dose of salmeterol.
Inhaled salmeterol, a beta 2-agonist, causes bronchodilation by relaxing the smooth muscle in the airway.
Formoterol action occurs by the formoterol molecules initially diffusing into the plasma membrane of the lung cells, and then slowly being released back outside the cell where they can come into contact with the beta-2 adrenoceptors.
Long-acting anticholinergics and long acting beta agonists cause increased risks of tachyarrhythmias, myocardial ischemia, stroke and death.
Long-acting anticholinergics and long acting beta agonists cause Increase risk of cardiovascular events as shown by meta-analyses of randomized controlled studies.
Long acting beta-agonists should be used only as an add on to anti-inflammatory therapies because of the increased risk of respiratory-related death.
Long acting beta agonist are never appropriate first line or monotherapy for asthma.