What is the comparison between Formoterol (long-acting beta-2 adrenergic receptor agonist) and Salmeterol (long-acting beta-2 adrenergic receptor agonist)?

From the Guidelines

Formoterol and salmeterol are both effective long-acting beta-2 agonists (LABAs) for treating COPD, but the choice between them should be based on the patient's specific needs and symptom pattern, with formoterol potentially being more versatile due to its faster onset of action, as demonstrated in a systematic review comparing long-acting b-agonists 1.

Key Differences

• Formoterol has a faster onset of action, starting to work within 1-3 minutes, while salmeterol takes 10-20 minutes to start working.
• Both medications provide bronchodilation for approximately 12 hours and are commonly used as maintenance therapy, not for acute symptom relief.
• Formoterol has a dual role as both maintenance and rescue medication in some combination inhalers, while salmeterol is strictly for maintenance.

Clinical Considerations

• Both medications should be used with an inhaled corticosteroid in asthma patients to reduce the risk of serious asthma-related events.
• Common formoterol brands include Foradil and Oxis, while salmeterol is available as Serevent.
• Side effects for both include tremor, headache, and palpitations.
• A systematic review comparing tiotropium to long-acting b-agonists, including salmeterol and formoterol, found that tiotropium was associated with a lower rate of exacerbations, but the strength of this evidence was deemed moderate due to a serious risk of bias 1.
• Another review found that combination inhaled corticosteroid and long-acting b-agonist therapy reduced the number of exacerbations, but did not affect the rate of hospitalizations compared with long-acting b-agonist therapy alone, and resulted in better lung function, health-related quality of life, and reduced use of rescue medication 1.

From the Research

Comparison of Fomoterol and Salmeterol

• Fomoterol and salmeterol are both long-acting beta2-adrenoceptor agonists used in the treatment of asthma and chronic obstructive pulmonary disease (COPD) 2, 3.
• Studies have compared the efficacy and safety of formoterol and salmeterol in combination with inhaled corticosteroids (ICS) in patients with asthma 4, 5.
• A Cochrane review found that regular treatment with formoterol and an ICS versus regular treatment with salmeterol and an ICS resulted in similar rates of serious adverse events, including mortality and non-fatal serious adverse events 4.
• Another review found that the addition of formoterol or salmeterol to an ICS did not significantly increase the risk of fatal serious adverse events, but may increase the risk of non-fatal serious adverse events 5.

Efficacy of Fomoterol and Salmeterol

• Salmeterol has been shown to improve lung function and reduce symptoms in patients with COPD 2.
• Formoterol has been shown to improve lung function and reduce symptoms in patients with asthma 3.
• Combination therapy with formoterol and an ICS has been shown to be effective in improving lung function and reducing symptoms in patients with asthma 4.
• Combination therapy with salmeterol and an ICS has been shown to be effective in improving lung function and reducing symptoms in patients with asthma 6, 5.

Safety of Fomoterol and Salmeterol

• The safety of formoterol and salmeterol has been evaluated in several studies, with most finding similar rates of serious adverse events between the two treatments 4, 5.
• However, some studies have suggested that salmeterol may be associated with a slightly increased risk of non-fatal serious adverse events compared to formoterol 5.
• The use of formoterol and salmeterol in combination with an ICS is generally considered safe, but patients should be monitored for potential adverse events 4, 5.