Asthma & COPD
13 Oct 2020Asthma and chronic obstructive pulmonary disease are common respiratory disorders. Effective treatment and monitoring is necessary to avoid complications that can develop due to poor oxygen saturation or exacerbation of the disorder.
Asthma is a disorder in which the bronchial tubes tighten as a result of inflammation; this then creates difficulty breathing due to the narrowing of the lumen of the airway. This happens in recurrent episodes and can be caused by a number of triggers. These triggers can include: exercise, aerosols, cold air, dust, cigarette smoke and more.
The condition often develops in childhood and can have differing severity amongst patients. Some suffers can avoid the use of medication entirely, whereas others will need a variety of medication in a treatment plan to effectively manage their condition. This can have a profound impact on quality of life and can preclude suffers from activities or occupations that they might otherwise pursue. The lowest doses of medication that control symptoms should be used so as to avoid side-effects.
Chronic obstructive pulmonary disease (COPD) is the name of a collection of disorders where long term breathing problems and poor airflow are present. This is due to inflammation and damage within the lungs. It is typically caused by smoking, but some people that have never smoked can be affected. This can be due to a genetic cause of the disease. Asthma can lead to the development of COPD due to the narrowing of airways and inflammation that can be caused by asthma. Symptoms of COPD usually do not present until later in life and can include: increasing breathlessness, a persistent chesty cough, frequent chest infections and persistent wheezing.
COPD is a life limiting disorder as airflow obstruction is progressive. Exacerbations of the disorder are a frequent cause of hospitalisation. Due to the poor respiratory health of patients with COPD hospital acquired pneumonia can be a significant complication during hospitalisation which further worsens prognosis for these patients. An effective regimen with good patient compliance can reduce the risk of admission and therefore acquired infections.
Salbutamol is an intermittent therapy for asthma. One or two puffs of a metered dose inhaler containing this medication is used up to four times a day to help to relieve the symptoms of asthma when they are present. Patients should use this medication when they begin to notice symptoms such as wheezing, shortness of breath and tightness in the chest. It works by relaxing the muscles of the airways to the lungs.
Fluticasone is a regular preventer therapy which is taken twice daily. Doses of between 100 micrograms to 500 micrograms are given for adults. It works by reducing inflammation in the airways as well as reducing sensitivity to things that may trigger the symptoms of asthma. It is also used in the long term management of COPD to help provide relief from the symptoms of the disorder, as well as to try and reduce the number of exacerbations of COPD.
Montelukast is a leukotriene receptor antagonist. 10mg is taken once daily in the evening. It achieves its clinical effect by blocking the action of leukotriene on receptors contained within the lungs which results in decreased inflammation and relaxation of the muscle of the airways.
Long acting antimuscarinic receptor antagonists can be used in the treatment of asthma or COPD. Tiotropium is an example of a drug of this class. It is taken once daily and works by blocking the effect of a neurotransmitter on muscle. This relaxes the muscle and provides relief from constricted airways. It also provides a reduction in mucous secretion which can help patients with productive chesty coughs.
Common medicines for both these disorders are inhaled corticosteroids. These steroids share a large amount of side effects which can include: arrhythmias, dizziness, headache, hypokalaemia (with high enough doses), nausea, palpitations and tremor.
Antimuscarinic receptor antagonists cause many of the same side-effects: arrhythmias, dizziness, headache and nausea. However, due to their effect on muscarinic receptors they commonly cause dry mouth.
Proper inhaler technique is crucial to effective administration of medicines for these conditions. If a patient has poor technique then these local effect medications will not reach their intended area, or will do so in sub-optimal quantities to provide the intended clinical effect. With some inhaler devices a patient must have adequate lung function to deliver the drugs effectively to their lungs. This can be an issue, especially with patients with more advanced COPD. Some inhaler devices are able to deliver medications with greater velocity so that the patient themselves do not need to inhale with such force.
A patient should be assessed with spirometry to see which inhaler is suitable for them. Spirometry is a test that is used to monitor lung function and measures how much air a patient can inhale and exhale, and the force that they can generate as they perform these functions.
Patients will need to have a discussion with their doctor about how well their condition is managed. Patients will initially be started on a short-acting beta-2 agonist, such as salbutamol, to offer some relief of symptoms.
If this does not adequately control their condition then they will be offered maintenance therapy of an inhaled corticosteroid, such as fluticasone. If their asthma is still uncontrolled then there should be the addition of a leukotriene receptor antagonist to their treatment plan. The patient’s response to this treatment should be reviewed after 4 to 8 weeks.
If this therapy does not offer control of asthma, then a long-acting beta-2 agonist should be used. Salmeterol and formoterol are examples of drugs in this class. They are often given in a combination inhaler such as seretide or fostair.
Patients should be cautioned about the use of their medicines if they suffer from some conditions. A patient with an existing arrhythmia may not be suitable for corticosteroids due to the potential for these medicines to cause arrhythmias. Patients with diabetes need to monitor their blood glucose levels carefully as some of these medications can influence these levels. Patients with hypertension or cardiovascular disease can face adverse effects due to the effect of drugs used in treatment of asthma and COPD.