The inhaled corticosteroids used in respiratory medicine are in fact synthetic agonists of the glucocorticoid receptor (GR), a nuclear hormone receptor in the same family as the androgen, progesterone and mineralocorticoid receptors. GR agonists act to modulate expression of genes containing the glucocorticoid response element (GRE). Although complex, the response appears to include inhibition of the biosynthesis of pro-inflammatory prostaglandins and leukotrienes. Hence GR agonist drug action results in reduced airway inflammation, when administered by inhalation.
Inhaled corticosteroids, if used regularly, provide effective asthma control and are the preferred treatment for long-term control of mild, moderate, or severe persistent asthma symptoms. Common side-effects of taking inhaled corticosteroids can include a hoarse voice, sore throat and mild throat infections (e.g.. thrush). Inhaled corticosteroids prescribed at the low doses recommended for asthma control have not been shown to cause weak bones, growth suppression, weight gain or cataracts, which are some of the side-effects of high dose corticosteroid use. Systemic absorption may follow nasal administration particularly if high doses are used or if treatment is prolonged.
Corticosteroid tablets or liquid are used when a higher dose is needed to effect asthma control and this level of usage can cause some of the deleterious side-effects listed above.
Inhaled corticosteroids can be prescribed in combination medications which also contain long-acting bronchodilator (LABA) drugs, providing effective concomitant control of the two major contributors to asthma symptoms; inflammation and bronchoconstriction. Common side-effects of combination medications include rapid heart beat, tremor or nervousness, cough, throat irritation or hoarseness.
Single agent inhaled corticosteroids
Budesonide, prescribed for prophylaxis of asthma, allergic and nonallergic (vasomotor) rhinitis, nasal polyps and Crohn's disease and collagenous colitis. Rectal administration is used to treat ulcerative colitis involving rectal and recto-sigmoid disease.
Fluticasone, prescribed for prophylaxis of asthma, prophylaxis and treatment of allergic rhinitis and perennial rhinitis, nasal polyps, severe inflammatory skin disorders such as dermatitis and eczemas unresponsive to less potent corticosteroids and psoriasis
Ciclesonide, prescribed for prophylaxis of asthma, by inhalation of aerosol.
Beclometasone dipropionate, prescribed for prophylaxis of asthma, management of oral ulceration, prophylaxis and treatment of allergic and vasomotor rhinitis, , severe inflammatory skin disorders such as dermatitis and eczemas unresponsive to less potent corticosteroids, psoriasis and as an adjunct to aminosalicylates in acute mild to moderate ulcerative colitis
Combination medications
Budesonide plus formoterol (LABA), prescribed for maintenance therapy for asthma, and for patients with chronic obstructive pulmonary disease with forced expiratory volume <50% of predicted (per second)
Fluticasone plus salmeterol (LABA), prescribed for prophylaxis of asthma