___________________________________________________________ Asthma: Diagnosis and Management
Other Antiallergic Medications Similar to mast cell stabilizers, the concept of antiallergic medications as a separate category is under intense study. The idea behind antiallergic drugs is simple—eliminate the allergic reaction so allergic asthma symptoms are greatly reduced. Particularly, some studies have been undertaken to research the effectiveness of antihistamine medications on the long-term control of asthma symptoms. However, research generally shows that the effect of antihistamines for the control of asthma is modest, especially if the patient is receiving the recommended treatment with corticosteroids. If the patient also has allergic rhinitis, as many patients with asthma do, antihistamine medications may help to control the rhinitis with secondary benefits to asthma symptoms. While second-generation antihistamines (e.g., loratadine, cetirizine) have been reported to decrease emergency department visits, the NAEPP recommends against their routine use for home management of asthma, as patient delays in seeking treatment have been associated with home use of antihistamines. Data on the use of second-generation antihistamines suggest that they are safe for use during pregnancy [9; 10]. There are also some preliminary data that suggest that asthma and allergies may provide protection against adult malignant gliomas; however, it was also found that the long-term use of immune mediators such as antihistamine medications may be a cancer risk for developing gliomas [38; 39; 40]. Research is ongoing to determine the link between antihistamine response and cancer. Antileukotrienes Antileukotriene medications, introduced in 1996, were the first new class of asthma medications released in decades. Leukotrienes act as a communication system for the inflam- mation process. Antileukotrienes disrupt this communication process, reducing the effects of hyper-responsiveness in patients with asthma. There are two types of antileukotriene drugs: leukotriene synthesis inhibitors, which prevent these chemicals from being generated, and leukotriene receptor antagonists, which prevent the chemicals from delivering their messages by blocking their receptors [9; 11]. Antileukotrienes are strong and very effective in preventing exercise-induced asthma; they can also prevent the develop- ment of bronchospasm caused by aspirin and may be useful in milder forms of asthma. These medications may be useful in the management of moderate-to-severe asthma when combined with an inhaled corticosteroid but may not be as effective as other approaches. Common antileukotriene medications approved in the United States include montelukast, zafirlukast, and zileuton. Com- pared to other anti-inflammatory drugs, antileukotrienes may produce more serious side effects, including reversible liver problems, headache, and nausea. Healthcare providers should caution pregnant women against taking these medications. For patients receiving antileukotrienes, serum levels of the agent(s) should be checked regularly to monitor for potential liver problems. The use of antileukotrienes has been associated with
the rare condition Churg-Strauss syndrome. This condition usually occurs in adult patients with asthma, with an initial presentation of flu-like symptoms and blood vessel inflamma- tion. Other signs include eosinophilic rash, nasal polyps, and pulmonary infiltrates. Left untreated, Churg-Strauss syndrome can result in major organ damage and even death. The FDA issued a boxed warning for montelukast in 2020 [9; 10; 35]. Other Medications Mucolytics may be prescribed to patients with asthma to destroy or dissolve mucus buildup in airways; expectorants may be used to thin and loosen mucus. With mucus thinned, coughing and clearing the airways should become easier. However, the value of mucolytics and expectorants for patients with asthma is the subject of debate, as they do not halt the production of excess mucus or treat the underlying causal factors [9; 11]. Antibiotics are useful for combating bacterial infections throughout the respiratory system; most respiratory infections, however, are viral, and antibiotics would not be useful in these cases. In general, antibiotics do not eliminate common asthma triggers, nor do they contribute to shorter hospital stays after severe attacks [9; 11]. The NAEPP and GINA recommend against the routine use of antibiotics for asthma [8; 9]. Decongestants are found in over-the-counter cold remedies and can produce side effects of nervousness, nausea, and headache; these side effects increase when compounded with asthma medications with similar side effect profiles. Decongestants are usually not recommended for patients who have cardiac or prostate problems and should be carefully monitored if taken in conjunction with other asthma medications [11]. Research continues for new, improved decongestants. NONPHARMACOLOGIC MANAGEMENT The most effective nonpharmacologic intervention for the treatment and/or prevention of asthma at this time is trigger avoidance, which will be discussed in detail later in this course. Knowing and eliminating any possible asthma triggers is one of the most important elements of any management plan. Additionally, peak flow meter use and increased patient edu- cation contribute to an enhanced understanding and control of asthma symptoms. Immunotherapy and complementary medicine modalities have also been used by patients with asthma. Strong patient education and communication is vital to the successful management of asthma. Immunotherapy/Biologics For some patients, particularly those with allergy-induced asthma, immunotherapy may result in a reduction of airway sensitivity, which should help prevent asthma attacks. With immunotherapy, small amounts of diluted allergen are injected, causing the patient’s immune system to produce the antibodies associated with an allergic reaction. This process is repeated once or twice a week for three to four months, sensitizing the patient with gradually higher concentrations of allergen, until the body is able to tolerate the trigger without reaction.
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