According to the American Lung Association, approximately 20 million Americans have asthma (including 7 million children), with 5,000 deaths per year attributed to the disease. 8.7% of Coloradans have been told they have asthma, compared to a little over 10% of Nevada residents (the state with the highest prevalence of asthma) and 4.6% of Virginia residents (the state with the lowest).
Asthma is defined as a chronic inflammatory disorder of the airways, with symptoms that include episodes of chest tightness, shortness of breath, coughing and wheezing ( a whistling sound that occurs upon exhaling, due to the passage of exhaled air through unusually narrowed airways). Such symptoms are usually related to an allergic response in the airways, caused by an allergen (pollen, dust, tobacco smoke, etc.), an infection (such as a viral upper respiratory tract chest infection), exercise, or even harsh conditions such as cold wind, irritating the airways. Any of these factors can cause the airways to respond by narrowing and swelling, leading to the breathing difficulties and coughing associated with an asthma attack.
Some of the many risk factors for developing asthma include: a family history of asthma or allergies, smoking, being overweight, and an allergen-filled environment (such as working in the construction business).
There are a variety of medications used in the treatment of asthma, the most common of which are the beta-agonist bronchodilators (so-called because they cause widening or "dilation" of the airways or "bronchi", leading to increased and easier airflow), which constitutes a group of medications that include albuterol (brand name Ventolin). These are most commonly used as "rescue inhalers" (to reduce the severity and duration of a sudden asthma attack) and to prevent asthma attacks which are brought on by exercise (exercise-induced bronchospasm, or EIB). Most of them work quickly and have a short duration.
Other medications that cause bronchodilation are the methylxanthines, which include theophylline (brand name Quibron-T) and aminophylline. These are ineffective by inhalation and must be given orally (usually theophylline) or parenterally (usually aminophylline). They may also have an antiinflammatory effect on the airways and strengthen the contractions of a fatigued diaphragm. The anticholinergic group of medications (which include ipratropium and tiotropium -brand name Spiriva HandiHaler) also cause bronchodilation, but they are less effective than the beta-agonist group.
Corticosteroids (usually in inhalation form but sometimes taken orally too) are also used in the treatment of asthma, and are, in fact, the only therapy that has been clinically proven to reduce the risk of death from asthma (this is related to the inhalation route of administration). They increase the effectiveness of the beta agonist bronchodilators and prevent and reverse changes in the structure of the airways that are caused by asthma (remodeling). Some examples are beclomethasone (brand names QVar, Beclovent, etc), fluticasone (brand names Flovent Diskus, Flovent, etc)and mometasone (inhaled) and hydrocortisone, prednisone and dexamethasone (oral).
Mast cell stabilizers work by, as their name suggests, stabilizing the mast cell membrane (mast cells are responsible for releasing chemicals responsible for causing or exacerbating inflammation and allergic responses), thus reducing the inflammatory response which is associated with asthma. They do not cause bronchodilation. Examples are cromolyn (brand name Intal) and nedocromil (brand name Tilade). Cromolyn is the second drug of choice after the inhaled, short-acting beta-agonists for the prevention of EIB, and can be combined with them in more severe cases.
The last main group of medications used in the control of asthma are the leukotriene modifiers, that include montelukast (brand name Singulair) and zafirlukast (brand name Accolate). They reduce the inflammatory and bronchoconstrictive effects of a chemical called leukotriene D4, a key player in the asthmatic response. Zileuton (brand name Zyflo) actually inhibits the synthesis of this chemical.
The treatment plan for asthma usually consists of inhaled, short-acting beta-agonists for mild, intermittent asthma (like albuterol), then stepping up as the symptoms worsen should they do so, or using more medications in combination with the inhaled beta agonists if the patient is diagnosed with moderate or severe asthma. Inhaled beta agonists can be combined with an inhaled corticosteroid (like beclomethasone) if the mild intermittent asthma turns to mild persistent, then long-acting inhaled beta agonists (like salmeterol or formeterol) can be added if it becomes moderate asthma, and oral corticosteroids (like prednisone) added to the mix of it becomes severe (along with the option of adding leukotriene modifiers, mast cell stabilizers, methylxanthines, etc along the way should the patient not tolerate any of the more commonly used medications or should the addition provide better relief).
Of course, medications aren't the complete answer to controlling asthma. Patients should educate themselves on how to monitor their symptoms (such as using a peak flow meter at home on a regular basis for those with moderate or severe asthma) and make sure they strictly adhere to their prescribed regimen. Avoidance of known allergic asthma triggers (such as animals and cigarette smoke) is also beneficial. Quitting smoking is essential for those with asthma or at risk for it.