Allergy, Asthma | December 12, 2014 | Author: The Super Pharmacist
Asthma is a respiratory condition in which the bronchi, or tubes leading from the throat to the lungs, may become constricted, thus restricting the ability to breathe in. This may lead to oxygen deprivation, discomfort, reduced quality of life and can be life-threatening. Asthma may occur in childhood or adulthood, and become a chronic condition. The symptoms of asthma may include:
Asthma is associated with inflammation. This is a chemical process in the body that may increase the immediate temperature in areas where inflammatory molecules are released. This is done to destroy foreign bodies (or particulate matter from the environment) in the airways that may be present in inhaled air.
These inflammatory molecules are released by certain cells of the immune system, (e.g. eosinophils) which may be present in mucus. Asthma attacks (or the onset of this condition) may be triggered by many types of foreign bodies. These include:
Some conventional therapies for many asthma types include:
These are drugs that enhance the destruction of bacteria or fungi. However, long-term or high-volume use of these may result in adaptations in these micro-organisms that confer resistance to their actions. Therefore, recurrent infections may not be affected by the same antibiotics.
These are drugs such as triazoles which target fungi. These should only be used in cases of asthma definitively diagnosed as being associated with fungal species such as Aspergillus.
These are drugs that reduce inflammation, and therefore may treat pain and tissue damage in cases of asthma. They are associated with side-effects such as gastrointestinal distress and hormone response changes resulting in mood swings, weight gain or skin problems. Long-term corticosteroid use increases the risk of organ damage. Often these are used as inhaled corticosteroids, referred to as preventers, which reduces the systemic absorption, allows for a more potent localised effect, and reduces the incidence of previously mentioned side-effects.
These are drugs associated with the relaxation of smooth muscle tissue, referred to as relievers. These may be delivered by devices such as inhalers at the onset of airway constriction, and are popular in the treatment of asthma in children. Salbutamol is the most commonly used asthmatic treatment option.
There are many types of surgical procedures available for cases of severe asthma, including bronchial thermoplasty. These may alleviate airway constriction, thus improving air-flow to the lungs and other symptoms. Normally reserved for severe cases.
Some factors may affect the progression of or recovery from asthma. These include:
Obesity is linked to the increased severity of symptoms by some studies. Observations from these studies indicate that those who are obese and suffer from asthma, benefit less from treatment, find the control of their condition more challenging and require more healthcare resources in comparison to non-obese subjects. There is some evidence that weight loss leads to improvements in asthma symptoms and outcomes.
Non-adherence to treatment. This is associated with advanced cases of the condition in adults. Non-compliance may be related to common side-effects, some of which are outlined above, and the presence of comorbid (or additional and possibly associated) conditions.
Respiratory microbiome. There are a variety of different micro-organisms (e.g. bacteria) that normally inhabit the airways but do not adversely affect health, in a similar way to those found in a healthy gut.
This may be termed the respiratory microbiome. The microbiome has been found to be altered in patients with asthma compared to healthy people of similar demographics. This indicates that the normal balance of micro-organisms is disrupted or imbalanced in some cases of asthma, which increases the risk of the increased growth of micro-organisms that may cause damage or increased immune system activation. This may lead to further inflammation. Inflammation is associated with pain and damage to tissues which it affects. Therefore, asthma is often regarded as a disorder of innate immunity, and may require treatment as such.
There are many treatments for asthma that focus on modulating or reducing the activities of the immune system in this condition. These include:
Immunotherapy may be administered in subcutaneous (under the skin), sublingual (under the tongue, usually in the form of drops or tablets) or intravenous forms. This may give long-term, constant-dose treatment for chronic forms of asthma. Immunotherapy is often specifically designed or prescribed based on the allergen (e.g. bacteria, fungi) that is responsible for the onset of asthma. However, they are associated with side-effects. These may include:
These side-effects may restrict adherence to immunotherapy. A review of 23 clinical trials of sublingual immunotherapy found that the rate of side-effects in treatment groups ranged from 17% to 60%, in comparison to a rate of 8% to 14% in the corresponding groups receiving placebos. However, only two cases of anaphylaxis were found, which were in fact related to drug interactions with additional, non-trial medications.
A systemic review of 81 clinical trials with 9998 participants found that side-effects resulted in an overall drop-out rate of 14% (approximately 16% in the placebo groups and 17% for treatment groups).
These results indicate that immunotherapy may be tolerable for the majority of patients, but it should be noted that many of these trials monitored patients for a year or less, and this evidence does not often extend to post-market surveillance (which assesses adverse events and side-effects of drugs that have made it to the stage of commercial approval and use).
Immunotherapy may be highly specialised to individual cases of asthma, which could reduce healthcare resource use and medication reliance in the long term. However, many forms of this treatment are in need of further testing and development. Immunotherapy is associated with systemic reactions including anaphylaxis. However, the anti-IgE antibody omalizumab is associated with the prevention of these side-effects. This medication has been approved for use in Europe for cases of IgE-mediated asthma in children over six, adolescents and adults. It has been shown to treat asthma that is resistant to treatment with conventional medications such as corticosteroids effectively and safely.
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