Asthma is a worldwide disease, more common in urban than rural
areas and accounts for about 25 per cent of all non-tuberculous chest diseases.
It may occur at any age, but in 50 per cent of the patients, it starts before
the age often. It is more common in boys than in girls, but at the age of 30
years, the incidence is equal. About 25 to 30 per cent of asthmatic children
spontaneously recover during adolescence, while a few recover several years
later. Asthma occurring during adult life is more serious. The attacks are more
frequent and prolonged.
Treatment
With the advancement in the methodology of treatment, the life
expectancy of asthmatics have been considerably increased than in the past. The
management of bronchial asthma includes specific treatment aimed at removal of
the cause and symptomatic treatment.
Specific Treatment
If the cause of the asthma can be discovered, every effort
should be made towards its removal to provide complete and permanent relief. If
the patient develops symptoms of allergy, such as skin rashes, itching and
pruritus and running nose the possible allergen (substance causing allergy)
should be identified. Its removal is the most effective way of controlling
allergic asthma. If this is not possible, desensitization by using an extract
of specific allergen should be attempted. In many cases of allergic asthma, the
specific allergen is not identifiable and antiallergic drugs are tried. A few
patients of seasonal asthma are benefited by temporarily moving to another town
before the onset of a particular season, but this is not always feasible.
If infection is the cause, the person should protect himself from
stress and strain due to extremes of weather. Frequent attacks of common cold
may lead to asthma. Intensive treatment with a specific antibiotic must be
instituted immediately. The most common offending organisms are Pneumococci and
Haemophilus influenzae. In these infections, broad-spectrum antibiotics like
amoxycillin, cefuroxime or ampicillin are usually effective.
Symptomatic Treatment
The drugs used for providing symptomatic relief are those which
prevent bronchospasms or cause broncho-dilatation. These can be divided into
two groups: 1) for treatment during acute attack; and 2) for prevention and
heatment of chronic asthma.
For Acute Attack
Adrenergic Beta:-Receptor Simulants: Salbutamol (Asthalin,
Bronkotab, Ventrolin), Terbutaline (Bricanyl), Adrenaline
Stimulation of the adrenergic beta-receptors of the lungs causes
relaxation of the bronchioles and opens up the respiratory airway. Salbutamol
and terbutaline are most effective.
Salbutamol (Albuterol)
It is the most commonly used drug to produce dilatation of
narrowed airways in asthma. For acute attack it is given by inhalation (patient
inhales the drug by a deep inspiration with nose pinched; training is needed
for optimal results). Two types of inhalers are available.
Adrenaline
It has been the time tested' gold standard' for the termination
of acute attack of bronchial asthma. However, because it disturbs the heart
rhythm it is now used rarely and its use should be avoided. For the same reason
Isoprenaline is not used today.
Direct-Acting Drugs: Theophylline, Aminophylline, Deriphylline
Theophylline and its preparation, aminophylline, cause
dilatation of bronchioles by direct action. Aminophylline which contains
theophylline and ethylenediamine as a dissolving agent, is very frequently used
for providing immediate relief during an acute attack of bronchial asthma. In
this condition, aminophylline is given in a well-diluted solution by the
intravenous route. Theophylline is also given by the oral route along with
ephedrine and other drugs, for prevention of recurrence of asthmatic attacks.
These are discussed at the end of this chapter. Theophylline is more effective
when given at night to prevent occurrence of night time attacks.
Dosage: The average oral daily dose of theophylline is 100 to
200 mg given 3 to 4 times a day. This is generally not tolerated by most
patients. To provide immediate relief, aminophylline, containing 250 mg of
theophylline, is diluted in 20 ml of5% glucose and injected intravenously, very
slowly, over a period of 5 to 10 minutes. Deriphylline causes less gastric
irritation and is better absorbed.
Adverse Effects and Precautions: Theophylline is irregularly
absorbed and an effective dose given by mouth causes irritation in the
gastro-intestinal tract. So it should never be taken on an empty stomach. The
most common adverse effects are nausea, anorexia, and vomiting. A very quick
intravenous injection of undiluted theophylline may cause a sudden fall in
blood pressure, and irregular beating of heart.
