Asthma Treatment - Drugs Used In Bronchial Asthma

Who is More Likely to Suffer from Asthma?

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.