treatment

The aims of treatment are to:
1) abolish symptoms
2) restore normal or best possible lung function
3) reduce the risk of severe attacks
4) enable normal growth to occur in children
5) minimize absence from school or employment.




This involves:
1) patient and family education about asthma
2) patient and family participation in treatment
3) avoidance of identified causes where possible
4) use of the lowest effective doses of convenient medications to minimize short-term and long-term side-effects.


General Types of Treatment


Drug Treatment
- Is it administered as aerosols or powders directly into the lungs
- Its advantages include direct delivery into the airways and first-pass metabolism in the liver is avoided; thus lower doses are necessary and systemic unwanted effects are minimized.


Drugs used in asthma :


1) Short acting relievers :

a) inhaled B2 agonists (salbutamol or terbutaline)

2) Long acting relieve / disease controllers :
a) Inhaled long acting B2 agonists (salmeterol or formoterol)
b) Inhaled corticosteroid (beclomethasone, budisemide and fluticasone)
c) Compound inhaled salmeterol and fluticasone
d) Sodium cromoglicate
e) Leukoterine modifiers (montelukast, zafirlukast and zileuton)


3) Other agents with bronchodilator activity
a) Inhaled antimuscaranic agents (ipratropium and oxitropium)
b) Theophylline preparations
c) Oral corticosteroids (prednisolone)


4) Steroid-sparing agents
a) Methotrexate
b) Cislosporin
c) Intravenous immunoglobulins
d) Anti-IgE monoclonal antibody (omalizumab)


Classification of drugs used in asthma :


B2-adrenoceptor agonists
- most widely used bronchodilator preparations contain B2-adrenoceptor agonists that are
  selective for the respiratory tract and do not stimulate the B1 adrenoceptors of the
  myocardium.
- relax the bronchial smooth muscle and is very effective in relieving symptoms but does
  little for the underlying inflammatory nature of the disease.
- examples are Short-acting B-agonists (SABAs) such as salbutamol or terbutaline


Antimuscaranic bronchodilators
- Muscarinic receptors are found in the respiratory tract; large airways contain mainly M3
  receptors whereas the peripheral lung tissue contains M3 and M1 receptors
- Nonselective muscarinic antagonists – ipratropium bromide (20– 40 μg three or four times
  daily) or oxitropium bromide (200 μg twice daily) – by aerosol inhalation can be useful
  during asthma exacerbations






Anti-inflammatory drugs
- Sodium cromoglicate and nedocromil sodium prevent activation of many inflammatory
  cells, particularly mast cells, eosinophils and epithelial cells, but not lymphocytes, by
  blocking a specific chloride channel which in turn prevents calcium influx.


Inhaled corticosteroids
- Patients who have regular persistent symptoms (even mild symptoms) need regular
  treatment with inhaled corticosteroids
- Beclometasone dipropionate (BDP) is the most widely used inhaled steroid and other
  inhaled steroids include budesonide, fluticasone, mometasone and triamcinolone.
- The unwanted effects of inhaled corticosteroids are oral candidiasis (5% of patients), and
  hoarseness due to the effect of corticosteroids on the laryngeal muscles.
- Asthmatic patients who smoke are less responsive to inhaled corticosteroids, and
  additional therapy, e.g. with leukotriene receptor antagonists, is required.


Oral corticosteroids and steroid-sparing agents
- Oral corticosteroids may be necessary for those individuals not controlled on inhaled
  corticosteroids and the dose should be kept as low as possible to minimize the side
  effects


Cysteinyl leukotriene receptor antagonists (LTRAs)
- This class of drug targets one of the principal asthma mediators by inhibiting the cysteinyl LT1 receptor.
- Montelukast, pranlukast (only available in South East Asia) and zafirlukast are given orally
- LTRAs should be considered in any patient who is not controlled on low to medium doses of inhaled steroids
- LTRAs are particularly useful in patients with aspirin-intolerant asthma, in those patients requiring high dose inhaled or oral corticosteroids and in asthmatic smokers. Because these drugs are orally active they are helpful in asthma combined with rhinitis and in young children with asthma and/or virus associated wheezing.


Monoclonal antibodies
- It is a recombinant humanized monoclonal antibody that complexes with free IgE – omalizumab – blocking its interaction with mast cells and basophils.


Treatment for Severe Asthma


If patient is at home :
1) The patient is assessed. Tachycardia, a high respiratory rate and inability to speak in sentences indicate a severe attack.
2) If the peak expiratory flow rate is less than 150 L/min (in adults), an ambulance should be called.
3) Nebulized salbutamol 5 mg or terbutaline 10 mg is administered.
4) Hydrocortisone sodium succinate 200 mg i.v. is given.
5) Oxygen 40–60% is given if available.
6) Prednisolone 60 mg is given orally.


If patient is at hospital :
1) The patient is reassessed.
2) Oxygen 40–60% is given.
3) The peak expiratory flow rate is measured using a low-reading peak flow meter, as an ordinary meter measures only from 60 L/min upwards. Measure O2 saturation with a pulse oximeter.
4) Nebulized salbutamol 5 mg or terbutaline 10 mg is repeated and administered 4-hourly.
5) Add nebulized ipratropium bromide 0.5 mg to nebulized salbutamol/terbutaline.
6) Hydrocortisone 200 mg i.v. is given 4-hourly for 24 hours.
7) Prednisolone is continued at 60 mg orally daily for 2 weeks.
8) Arterial blood gases are measured; if the Paco2 is greater than 7 kPa, ventilation should be considered.
9) A chest X-ray is performed to exclude pneumothorax.
10) One of the following intravenous infusions is given if no improvement is seen:
a) salbutamol 3–20 μg/min, or
b) terbutaline 1.5–5.0 μg/min, or
c) magnesium sulphate 1.2–2 g over 20 min.


references : Mayo Clinic