Inhaled corticosteroids are medications that improve breathing by decreasing lung inflammation. They are primarily used in clients with persistent asthma, meaning those who have asthmatic symptoms more than 2 days per week.
Asthma is characterized by chronic inflammation in the lungs, as well as asthma exacerbations or attacks, where certain triggers, such as viruses, allergens, stress, aspirin or other NSAIDs and exercise, lead to reversible bronchial smooth muscle spasms and mucus production, both of which make it hard to breathe.
As a result, clients experience symptoms like dyspnea, wheezing, chest tightness, and coughing. Inhaled corticosteroids help decrease the frequency of symptoms and prevent exacerbations.
Inhaled corticosteroids can also be used in clients with chronic obstructive lung disease, or COPD, to prevent exacerbation and slow the progression of the disease.
Now, commonly used inhaled corticosteroids include fluticasone, beclomethasone, budesonide, and mometasone.
These medications are typically used as maintenance therapy to help control the underlying lung inflammation, and are often combined with inhaled bronchodilators, such as long acting beta-2 agonists like salmeterol, which provide immediate relief of symptoms by inducing airway smooth muscle relaxation.
Now, once in the lungs, inhaled corticosteroids enter the respiratory epithelial cells and suppress the expression of certain genes that code for inflammatory proteins.
This leads to decreased movement of inflammatory and immune cells into the bronchi and lungs, as well as decreased production and release of inflammatory mediators like histamine and leukotrienes.
As a result, there’s reduced airway inflammation and edema, as well as decreased mucus production, which ultimately leads to airway dilation and improved air flow.
Because they work on the gene level, inhaled corticosteroids may need days or even weeks to demonstrate effectiveness.
That's why they are only used to prevent exacerbations of asthma and COPD and should not be used to treat acute episodes.
Since inhaled corticosteroids control the underlying lung inflammation, clients will need to take them daily even when they feel well.
Now, inhaled corticosteroids mainly cause localized side effects that result from the deposits left in the mouth or larynx as they travel down into the lungs.
Inhaled corticosteroids weaken the immune defense mechanisms in the mouth, which can lead to infection by the fungus Candida albicans, and results in oropharyngeal thrush.
Prolonged use of corticosteroids can also result in immunosuppression, which may cause or prolong respiratory tract infections like pneumonia. Other side effects of inhaled corticosteroids include a sore throat, hoarseness, and cough.
Less commonly, inhaled corticosteroids are associated with other side effects, especially when used in high doses and for a long duration. These include hypercortisolism and suppression of the hypothalamic–pituitary–adrenal axis.
As a result, if the client abruptly stops using corticosteroids, the adrenal glands may be unable to produce enough cortisol.
Additional side effects of inhaled corticosteroids include increased appetite and weight gain, increased risk of fractures, osteoporosis, and decreased bone growth rate in children.
Now, in general, inhaled corticosteroids are considered to be safe and effective medications, however, they are contraindicated in clients who have an active respiratory tract infection, like pneumonia or tuberculosis, and they should be used with caution in those with cataracts or glaucoma, since corticosteroids can make these conditions worse.
