Formoterol

Overview
Formoterol (INN) or eformoterol (former BAN) is a long-acting β2-agonist used in the management of asthma and/or chronic obstructive pulmonary disease (COPD). It is marketed in both dry-powder inhaler (DPI) and metered dose inhaler (MDI) preparations, under various trade names including Foradil/Foradile (Novartis) and Oxis (AstraZeneca).

Formoterol is a long-acting β2 agonist (LABA), which has an extended duration of action (up to 12 hours) compared to short-acting β2 agonists such as salbutamol, which have are effective for 4–6 hours. LABAs such as formoterol are used as "symptom controllers" to supplement "preventer" corticosteroid therapy (e.g. fluticasone). A "reliever" short-acting β2 agonist (e.g. salbutamol) is still required, since LABAs are not recommended for the treatment of acute asthma.

Mechanism of action
Inhaled formoterol works like other β2-agonists, causing bronchodilatation by relaxing the smooth muscle in the airway so as to treat the exacerbation of asthma. The long duration of formoterol action occurs because the formoterol molecules initially diffuse into the plasma membrane of the lung cells, and then are slowly released back outside, where they can come into contact with β2 adrenergic receptors. Formoterol has been demonstrated to have a faster onset of action than salmeterol as a result of lower lipophilicity, and has also been demonstrated to be more potent - a 12 µg dose of formoterol has been demonstrated to be equivalent to a 50 µg dose of salmeterol.

Safety
In November of 2005, the American FDA released a health advisory, alerting the public to findings that show the use of long-acting β2-agonists could lead to a worsening of symptoms.

Currently available long-acting β2-agonists include salmeterol, formoterol, bambuterol, and sustained-release oral salbutamol. Combinations of inhaled steroids and long-acting bronchodilators are becoming more widespread – combination preparations include fluticasone/salmeterol and budesonide/formoterol.