Question

1. Asthma used to be treated primarily with bronchodilators and anti-inflammatories like corticosteroids were avoided.  Why has the thinking on this changed? Why are inhaled corticosteroids used so frequently as a maintenance medication?

Answer 1

Although asthma used to be treated historically with bronchodilators, this preference has changed and now corticosteroids are used as first-line treatment for patients with asthma. This thinking has changed due to a better understanding of mechanisms responsible for symptoms in asthma patients and the availability of newer, safer corticosteroids and advancement in methods of drug delivery.

Bronchodilators act by dilating the airway and relieves symptoms immediately or make it easier to breathe, but these drugs do not solve the underlying pathophysiological processes that are responsible for the appearance of asthma symptoms. Hence they provide symptomatic relief only.

Corticosteroids have been used successfully to treat asthma for over 50 years and are now recommended as first-line therapy for controlling asthma in asthmatic patients of all ages and severity.

Corticosteroids act by suppressing airway inflammation and controlling the production of mucus, reducing airway hypersensitivity or hyperresponsiveness, and preventing constriction of the airway. At a cellular level corticosteroids reduce the numbers of inflammatory cells in the airway including eosinophils, T-lymphocytes, mast cells, macrophages and dendritic cells. They also suppress the production of chemical mediators of inflammation (cytokines, chemokines, adhesion molecules inflammatory enzymes and receptors).

Therefore steroids act by suppressing the basic pathophysiological processes involved in asthma symptoms or suppress the processes responsible for the occurrence of symptoms.

· Other than this inhaled corticosteroids mimic the hormone cortisol, which is naturally produced by the body. These inhaled corticosteroids are not anabolic steroids that are misused by some athletes to build muscle.

· They are prescribed in the lowest dosages and act locally when inhaled, so no systemic side effects. They are also not habit-forming or create dependence.

· They are safe for adults and children especially at lower doses.

· Inhaled corticosteroids don't generally cause serious side effects.

· Mild side effects like oral thrush (a yeast infection in the mouth) and hoarseness, although rare, but may occur. Rinsing mouth/ gargling after inhaler, and using a spacer device with metered-dose inhalers can help prevent these side effects.

· They have shown to improve the quality of life of patients with asthma by

1. Reducing the frequency of asthma attacks

2. Decreasing use of beta-agonist bronchodilators (quick-relief or rescue inhalers)

3. Improving lung function

4. Reducing emergency room visits and hospitalizations for life-threatening asthma

5. may prevent irreversible airway changes.

Examples of inhaled corticosteroids are beclomethasone, budesonide, ciclesonide, flunisolide, fluticasone and triamcinolone. Long-acting β2-agonists can be added to further improve asthma control and are commonly given as combination inhalers, which improve compliance and control asthma at lower doses of corticosteroids.

Bronchodilators are non-steroid medications that open airways by relaxing the small muscles of the airway. They come in both short-acting (lasting four to six hours) and long-acting (lasting 12 or more hours) versions. Short/ rapid-acting bronchodilators are used as "rescue" or quick-relief medications to immediately relieve asthma symptoms at times of flare-up. They include albuterol, levalbuterol, terbutaline and ipratropium.

Long-acting bronchodilators (beta 2-agonist bronchodilators ) are used to provide asthma control in patients who are not manageable by corticosteroids alone or in patients with COPD. They should only be used in conjunction with inhaled steroids for long-term control of asthma symptoms. Examples are salmeterol and formoterol. They are given on a regular (daily) basis, rather than need-based.