Asthma medication

Asthma medication is designed to reverse the constriction of bronchi that causes the difficulty breathing in asthma. Steroid based drugs also reverse the inflamatory process which occurs during asthma attacks. Untreated inflamation is thought to cause permanent damage to the lung tissues. Most are given by inhaler, but there are syrups that can be taken.

Anti-asthmatic drugs can be categorised as: relievers, symptom controllers and preventers, depending on their method of action and duration. There are also other drugs that may be used in a hospital setting.

Various protocols exist to decide how to treat a person with asthma. One of these is a stepwise approach for managing asthma for both adults and children, designed by the Global Initiative for Asthma (GINA). This grades the severity of the asthma and gives an appropriate drug regime. Depending on the results, a patient can step up or down in severity, and take less or more medication.

Contents

1 Relievers 2 Symptom controllers 3 Preventers 4 Other drugs 5 Alternative Medicine 6 References

Relievers

Asthma relievers such as salbutamol (Ventolin) or terbutaline are designed to quickly dilate the smooth muscle of the bronchi, enabling air to flow more freely. They normally come in a blue inhaler.

They are selective β₂ agonists and work on adrenergic receptors in the lungs. (These are the same receptors adrenaline works on, except adrenaline has more effects on other tissues such as the heart.)

Many of the side effects of β₂ agonists are caused by their actions on other tissues, and can potentially cause tremors and tachycardia (fast heart rate). This is because the drugs have a small action on other receptors, and also because there are a few β₂ receptors in the heart.

These are inhaled if breathing becomes difficult. The best way to take them is to have one puff, then wait a minute, and then have another puff. Doing this allows the larger airways to dilate, letting the drug get through to the smaller airways on the second puff.

With chronic use, the airways of the lungs get slightly desensitised to the actions of these preventers.

Symptom controllers

Symptom controllers are long acting β₂ agonists. They are similar in structure to the relievers, but have much longer sidechains. Examples include salmeterol, formoterol and bambuterol.

Preventers

Asthma attack preventers are corticosteroids, that can be inhaled or taken orally, and work by altering the production of chemicals that cause the asthmatic response.

There are many corticosteroids around, such as beclomethasone, fluticasone, dexamethasone and prednisolone. They are often in brown-coloured inhalers, and are marketed with names such as Becotide, Flixotide and Pulmicort.

Long-term use of corticosteroids can have many side effects. Corticosteroids can cause a redistribution of fat, increased appetite, blood glucose problems, and weight gain. They also cause thinning of the skin, osteoporosis and decreased immunity and slower healing.

Because of these side effects, the dose of corticosteroid should be minimised. For this reason inhaled steroids should be used for prevention, as they are more targeted to the lungs than oral preparations.

When using inhaled corticosteroids, (or any drug from an inhaler), even with the best technique, most gets deposited in the mouth and does not reach the lungs. The corticosteroids can then cause a hoarse voice or oral thrush (due to decreased immunity). The chance of these side effects can be minimised by rinsing the mouth with water after inhaler use, as well as by using a spacer which increases the amount of drug that reaches the lungs.

The frequency of use should be minimised. For example, four puffs twice a day is better than two puffs four times a day.

Other drugs

According to one on-line listing, there are >50 drugs available for the treatment of asthma¹. In addition, there are >200 clinical trials for treatments taking place across 40 states according to one clinical trial registry².

• Theophylline or aminophylline
• Leukotriene antagonists (e.g. montelukast, zafirlukast)
• Cromoglycate-based mast cell stabilisers
• Antihistamines

Alternative Medicine

• Pipal (Ficus religiosa) also known as Bo-tree leaves dried and crushed can be taken twice a day (one spoonful) with luke warm water as per the Indian Ayurveda system of medicine.
• MatsyaAsan or the Fish Pose as per the Indian Yoga sytem helps Asthama patients considerably.

References

Note 1: Asthma: Index of Commonly Prescribed Medications (http://www.healthsquare.com/nav_indices/asthma_index2.htm). Retrieved 2005-02-05. Note 2: Clincal Trials: Asthma (http://www.centerwatch.com/patient/studies/cat16.html). Retrieved 2005-02-05.pt:Antiasmático