Glucocorticoids have been employed in the treatment of asthma for a long time, and are especially useful in the management of severe chronic asthma or severe acute exacerbations. These drugs are usually given systemically, but the development of aerosol formulations in recent years has greatly improved the efficacy as well as safety.
Examples include beclomethasone dipropionate, triamcinolone acetonide, flunisolide, budesonide dipropionate, and flutica-sone propionate. Adverse and toxic effects have been listed in Table 32.4. Of all the inhaled corticosteroids, fluticasone is said to be the safest, being associated with a low incidence of adverse effects. Treatment involves cessation of inhaled glucocorticoids. Oropharyngeal candidiasis can be prevented by rinsing the mouth and throat with water after each use and by employing spacer or reservoir devices attached to the dispenser.
Cromolyn was first synthesised in 1965 and has been in use in the management of asthma since 1973. It is the first-line drug for the treatment of mild to moderate asthma. It is also used as eye drops in the treatment of allergic conjunctivitis. A related compound, Nedocromil was released for use recently.
Mode of action is through inhibition of pulmonary mast cell degranulation in response to a variety of stimuli, and suppression of activating effects of chemoattractant peptides on human neutrophils, eosinophils, and monocytes. Cromolyn and nedocromyl are administered by inhalation using either solution (delivered by aerosol spray or nebuliser), or powdered drug (delivered by turbo-inhaler). Only about 1% of an oral dose of cromolyn is absorbed. After inhalation, peak plasma concentrations occur within 15 minutes. The biological half-life ranges from 45 to 100 minutes.
Adverse effects are uncommon with both cromolyn and nedocromil. Occasional effects reported include cough, bronchospasm, laryngeal oedema, joint pain, headache, rash, angioedema, and nausea. Nedocromil may leave behind a bad taste.