Drugs used for asthma can be divided into two categories:
Drugs that treat the muscle spasm in the wind pipe (bronchodilators)
These drugs are very useful to relieve the symptoms of asthma. There are two types in this category short acting and long acting beta agonists. Short acting drugs (salbutamol, terbutaline) will be effective only for a short time and is useful in those who get occasional symptoms.
Long acting beta agonists (salmeterol, Formeterol) are effective for more than 12 hours. If taken 12 hourly, these drugs are found to be effectively controlling symptoms in those patients who suffer from persistent severe symptoms.
Theophyllines are used sometimes in those patients who could not get relief of symptoms by using long acting beta agonists. They have potential side effects even with a small excess of medication dose. Unfortunately factors like viral infection, smoking, oral contraceptive pills and many other drugs could change the concentration of this drug in the blood causing severe side effects. This drug should be taken only under strict medical supervision.
Doctor may try a medication called ipratropium bromide (atrovent) in some patients who gets chest tightness due to emotion, stress or exposure to cold air.
Drugs that prevent inflammation.
This drug is normally used as either using inhaler (betamethasone) or as tablets (prednisolone). Steroid inhalers are used for long term treatment of asthma. They effectively prevent asthma. Side effects due to regular use of Steroid inhalers are minimal as they contain only small amount of drug. Several studies has shown the side effects while using steroid inhalers occurs if the dose exceeded 400 mcg in children and 800 mcg in adults. Most important side effect is development of oral thrush. If you use a dry powder form of steroid inhaler, you can prevent the oral thrush by rinsing your mouth after you have taken the medicine.
Corticosteroid tablets have a definite place in acute episode of asthma not controlled by inhalers. Normally a 5 day course of high dose oral steroid will be given (prednisolone). With this short therapy, side effects are minimal compared to long term steroid tablets. In some patients where none of the medication is helping, doctor might try long term steroid tablets. But taking long term steroids may give many side effects and should be taken only under expert supervision. The common side effects are easy bruising, water retention, high blood pressure, muscle weakness, diabetes, osteoporosis etc
Cromones (Sodium chromglycate):
This drug may be used sometimes in combination with other drugs. By combining this drug, your doctor may be able to reduce the dose of other medications like steroid inhalers.
Leukotriene antagonists (Montelukast and zafirlukast):
These drugs are useful as add on treatment for those patients whose symptoms are not even controlled even after taking short acting beta agonists and steroid inhalers. But using this drug alone without other inhalers may not give adequate benefit.
In some patient where common drugs are not helping, drugs like methotrexate could have been used to reduce the severity of the asthma. Patient who is taking this medication would be normally under the supervision of an expert in asthma and would get regular blood tests.
Human body produces antibodies (a type of protein) in response to any foreign protein that enters inside. These foreign proteins are either bugs like bacteria, virus or they may be allergens. These antibodies attach them to the receptors of two types of specialized cells (basophiles and mast cells) and make these cells to release some chemicals which lead to swelling and inflammation. Scientists have successfully developed a special monoclonal antibodies (antibodies produced in the laboratory by a single clone of cells) called Omalizumb. This medication has a tendency to prevent the normal antibodies attaching to the specialized cells so preventing inflammation. Unfortunately this drug is helpful only in certain cases of asthma. Also its use is somewhat limited due to side effects like anaphylactic reaction, erythema and pain at the injection site and risk of some parasitic infection.
This article is the Fifth part of “Walking with a Doc Series – Asthma.”