Inhalational steroids are most typically used in asthma and rhinitis, and less commonly in COPD (emphysema, Bronchiectasis). They are delivered through pMDI (pressurized metered dose inhaler), spacer, rotacap, or nasal sprayer. Drugs include:
- Beclomethasone dipropionate
It is an inhalational preparation of beclomethasone. 50 mcg, 100 mcg, 200 mcg per metered dose inhalers are available for the use. Intranasal spray (50 mcg in each nostril BD–TDS) is effective in perennial rhinitis.
It is a nonhalogenated glucocorticoid with a higher topical: systemic action ratio than beclomethasone as well as faster first-pass metabolism. Small fraction that is absorbed is quickly metabolised hence less systemic effects. Dosage: 200–400 mcg BD–QID by inhalation in asthma and 200–400 mcg/day by intranasal spray for allergic rhinitis.
It is a prodrug that’s broken into the active moiety by esterases in the bronchial epithelium. Despite the fact that it is absorbed by the lungs, oral bioavailability is less than 1%. It is highly bound to plasma proteins in the circulation, reducing tissue cell exposure to the free and active drug. Thus, it achieves high topical: systemic action ratio. Dosage: 80–160 mcg by inhalation daily, preferably in the evening.
This inhaled glucocorticoid has a high potency (about double that of beclomethasone), a prolonged half-life, and low oral bioavailability. The dose taken after inhalation has a low chance of causing systemic effects. Dosage: 100–250 mcg twice daily (max 1000 mcg/day) by inhalation. In patients who require larger doses, this may be suitable.
This steroid is available for prophylaxis and treatment of seasonal and perennial rhinitis. Dosage: 25 mcg per propulsion nasal spray; one spray in each nostril, 2–3 times daily.
The most common adverse effects include:
- asymptomatic or symptomatic oropharyngeal candidiasis.
- hoarseness of voice
- sore throat
These adverse effects can be reduced by using a spacer, gargling after each dose (to wash off the drug deposited on the oral and pharyngeal mucosa). Topical nystatin or clotrimazole can be used to prevent as well as treat them. Even after continuous use, there is no evidence of mucosal injury or an increased frequency of chest infections.
Inhalational steroids’ role in asthma
The ICSs (inhalational corticosteroids) reduce airway hyperresponsiveness and inflammatory mediator formation, in a few hours. The peak effect occurs 5–7 days after starting inhaled steroids, and the benefit lasts for a few weeks after stopping them. However, maximum effects on airway hyperresponsiveness may take several weeks or months. Inhaled steroids minimize the requirement for rescue β2-agonist inhalations and help to prevent acute asthma attacks. Long-acting β2-agonist should not be prescribed for the treatment of asthma without concurrent anti-inflammatory therapy, according to most experts. although, ICSs have no role during an acute attack or in status asthmaticus. Steroids potentiate the effects of β agonists on bronchial smooth muscle and prevent and reverse β receptor desensitization in airways.
Doses of less than 400 mcg BDP or equivalent can provide the majority of the benefit in asthma. Higher doses (up to 2000 mcg/d) may be required to some patients with relative corticosteroid resistance.
The lowest dose of ICS that controls asthma should be used; after control is obtained, the dose should be gradually reduced. Administration once daily of some steroids (e.g., budesonide, mometasone, and ciclesonide in mild asthma and fluticasone furoate in all patients) is effective when doses of 400 mcg or less are needed. If a dose greater than 800 mcg daily is required, a spacer device should be used instead of a pressurized metered dose inhaler (pMDI), to reduce the risk of oropharyngeal side effects.
ICSs may be used in children in the same manner as in adults; at doses of 400 mcg/d or less, there is no evidence of significant growth suppression. Nebulized corticosteroids (e.g., budesonide) are useful in the treatment of small children who are not able to use other inhaler devices.
Corticosteroids have a limited effect on airway inflammation in COPD. As a consequence, in advanced COPD with repeated exacerbations, only high-dose inhaled steroids are effective. ICSs have no effect on the progression of COPD or the COPD related mortality.