What are the effects of inhaled corticosteroids (ICS) for asthma?

From the Guidelines

Inhaled corticosteroids (ICS) are the preferred treatment for asthma, as they improve asthma control more effectively than any other single long-term control medication, and should be taken daily on a long-term basis to achieve and maintain control of symptoms. The use of ICS has been shown to improve asthma outcomes, including prebronchodilator forced expiratory volume in 1 second (FEV1), reduced hyperresponsiveness, improvements in symptom scores, fewer courses of oral corticosteroids, and fewer urgent care visits or hospitalizations 1.

Key Points to Consider

• ICS are the foundation of care for persistent asthma and should be used in conjunction with a spacer device for metered-dose inhalers to improve medication delivery to the lungs and reduce side effects.
• The dosage of ICS can range from low to high depending on asthma severity, with low doses often sufficient for mild persistent asthma and medium to high doses required for moderate to severe asthma.
• ICS have minimal systemic side effects when used at recommended doses, making them safe for long-term use 1.
• Patients should understand that ICS are controller medications that prevent symptoms rather than provide immediate relief during an asthma attack.

Comparison to Other Medications

• Studies have shown that ICS are more effective than other long-term-control medications, such as cromolyn, nedocromil, theophylline, or leukotriene receptor antagonists (LTRAs), in improving asthma outcomes 1.
• Combining long-acting beta agonists and ICS is effective and safe when ICS alone are insufficient, and such combinations are an alternative to increasing the dosage of ICS 1.

Clinical Implications

• The use of ICS should be guided by the NAEPP Expert Panel Report 2: Guidelines for the Diagnosis and Management of Asthma (EPR-2) stepwise approach to therapy.
• Patients should be educated on the proper use of ICS, including the importance of daily use, proper inhaler technique, and rinsing the mouth after use to prevent oral thrush.

From the FDA Drug Label

The precise mechanism of corticosteroid actions on inflammation in asthma is not well known. Inflammation is an important component in the pathogenesis of asthma Corticosteroids have been shown to have a wide range of inhibitory activities against multiple cell types (e.g., mast cells, eosinophils, neutrophils, macrophages, and lymphocytes) and mediators (e.g., histamine, eicosanoids, leukotrienes, and cytokines) involved in allergic- and non-allergic-mediated inflammation. The anti-inflammatory actions of corticosteroids may contribute to their efficacy in asthma Improvement in the control of asthma symptoms following inhalation of budesonide inhalation suspension can occur within 2 to 8 days of beginning treatment, although maximum benefit may not be achieved for 4 to 6 weeks Budesonide administered via a dry powder inhaler has been shown in various challenge models (including histamine, methacholine, sodium metabisulfite, and adenosine monophosphate) to decrease bronchial hyperresponsiveness in asthmatic patients.

The effects of inhaled corticosteroids (ICS) for asthma include:

• Anti-inflammatory actions: ICS have inhibitory activities against multiple cell types and mediators involved in inflammation
• Rapid symptom improvement: Improvement in asthma symptoms can occur within 2 to 8 days of beginning treatment
• Decreased bronchial hyperresponsiveness: ICS can decrease bronchial hyperresponsiveness in asthmatic patients
• Maximum benefit: Maximum benefit may not be achieved for 4 to 6 weeks 2

From the Research

Effects of Inhaled Corticosteroids (ICS) on Asthma

• Inhaled corticosteroids are the recommended first-line treatment for asthma, as they suppress inflammation in asthmatic airways and inhibit almost every aspect of the inflammatory process in asthma 3.
• ICS are effective in most patients with asthma, irrespective of age or asthma severity, and control asthma symptoms, improve lung function, prevent exacerbations, and may reduce asthma mortality and the irreversible changes in airway function that occur in some patients 3.
• The dose-response curve to inhaled corticosteroids is relatively flat, and adding another class of therapy, such as long-acting inhaled beta2-agonists, low-dose theophylline, or antileukotrienes, may be preferable to increasing the dose of inhaled corticosteroids in patients with moderate-to-severe asthma 3.

Clinical Efficacy and Dosing Options

• Combination therapy with inhaled corticosteroids and long-acting beta2-agonists is a recognized treatment for adults with moderate to severe asthma, and simplifies treatment and improves asthma control 4.
• Once-daily evening treatment with fluticasone furoate is an efficacious and well-tolerated treatment for asthma patients and is not inferior to the same total twice-daily dose 5.
• Inhaled corticosteroids have a favourable therapeutic profile, with a low risk of systemic adverse effects, and are the most cost-effective treatment currently available for long-term asthma control 3, 6, 7.

Comparison with Other Treatments

• Inhaled corticosteroids are more effective than leukotriene receptor antagonists as initial maintenance therapy for persistent asthma, with greater improvements in lung function, asthma control, and quality of life 7.
• Combination therapy with an inhaled corticosteroid and a long-acting beta2-agonist is more effective than treatment with a single-controller agent alone, and is associated with significantly lower healthcare costs and less frequent use of healthcare resources 7.