Asthma: Encyclopedia II - Asthma - Treatment

Asthma - Treatment

The most effective treatment for asthma is identifying triggers, such as pets or aspirin, and limiting or eliminating exposure to them. Desensitization is commonly attempted, but has not been shown to be effective. As is common with respiratory disease, smoking adversely affects asthmatics in several ways, including an increased severity of symptoms, a more rapid decline of lung function, and decreased response to preventive medications.^[9] Asthmatics who smoke typically require additional medications to help control their disease. Furthermore, exposure of both nonsmokers and smokers to secondhand smoke is detrimental, resulting in more severe asthma, more emergency room visits, and more asthma-related hospital admissions.^[10] Smoking cessation and avoidance of those who smoke is strongly encouraged in asthmatics.^[11]

The specific medical treatment recommended to patients with asthma depends on the severity of their illness and the frequency of their symptoms. Specific treatments for asthma are broadly classified as relievers, preventers and emergency treatment. The Expert panel report 2: Guidelines for the diagnosis and management of asthma (EPR-2)^[11] of the U.S. National Asthma Education and Prevention Program, and the British guideline on the management of asthma ^[12] are broadly used and supported by many doctors. Bronchodilators are recommended for short-term relief in all patients. For those who experience occasional attacks, no other medication is needed. For those with mild persistent disease (more than two attacks a week), low-dose inhaled glucocorticoids—or alternatively, an oral leukotriene modifier, a mast-cell stabilizer, or theophylline—may be administered. For those who suffer daily attacks, a higher dose of glucocorticoid in conjunction with a long-acting inhaled β-2 agonist may be prescribed; alternatively, a leukotriene modifier or theophylline may substitute for the β-2 agonist. In severe asthmatics, oral glucocorticoids may be added to these treatments during severe attacks.

For those in whom exercise can trigger an asthma attack (exercise-induced asthma), higher levels of ventilation and cold, dry air tend to exacerbate attacks. For this reason, activities in which a patient breathes large amounts of cold air, such as cross-country skiing, tend to be worse for asthmatics, whereas swimming in an indoor, heated pool, with warm, humid air, is less likely to provoke a response.^[4]

Asthma - Relief medication

Symptomatic control of episodes of wheezing and shortness of breath is generally achieved with fast-acting bronchodilators. These are typically provided in pocket-sized, metered-dose inhalers (MDIs—see the image to the right). In young sufferers, who may have difficulty with the coordination necessary to use inhalers, or those with a poor ability to hold their breath for 10 seconds after inhaler use (generally the elderly), an asthma spacer (see top image) is used. The spacer is a plastic cylinder that mixes the medication with air in a simple tube, making it easier for patients to receive a full dose of the drug and allows for the active agent to be dispersed into smaller, more fully inhaled bits. A nebulizer—which provides a larger, continuous dose—can also be used. Nebulizers work by vapourizing a dose of medication in a saline solution into a steady stream of foggy vapor, which the patient inhales continuously until the full dosage is administered. There is no clear evidence, however, that they are more effective than inhalers used with a spacer. Nebulizers may be helpful to some patients experiencing a severe attack. Such patients may not be able to inhale deeply, so regular inhalers may not deliver medication deeply into the lungs, even on repeated attempts. Since a nebulizer delivers the medication continuously, it is thought that the first few inhalations may relax the airways enough to allow the following inhalations to draw in more medication.

Relievers include:

• Short-acting, selective beta₂-adrenoceptor agonists (salbutamol [albuterol], levalbuterol, terbutaline, bitolterol, pirbuterol, procaterol, fenoterol, reproterol). Tremors, the major side effect, have been greatly reduced by inhaled delivery, which allows the drug to target the lungs specifically; oral and injected medications are delivered throughout the body. There may also be cardiac side effects at higher doses (due to Beta-1 agonist activity), such as elevated heart rate or blood pressure; with the advent of selective agents, these side effects have become less common. Patients must be cautioned against using these medicines too frequently, as with such use their efficacy may decline, producing desensitization resulting in an exacerbation of symptoms which may lead to refractory asthma and death.
• Older, less selective adrenergic agonists, such as inhaled epinephrine and ephedrine tablets—both of which, unlike other medications, are available over the counter in the US under the Primatene brand. Cardiac side effects, although uncommon, occur more often with the less selective drugs. They also provide a shorter period of relief than the selective bronchodilators. Nowadays, they are usually avoided in patients with heart disease. In emergencies, these drugs were sometimes administered by injection. Their use in this situation has declined.
• Anticholinergic medications, such as ipratropium bromide may be used instead. They have no cardiac side effects and thus can be used in patients with heart disease; however, they take up to an hour to achieve their full effect and are not as powerful as the β₂-adrenoreceptor agonists.

Asthma - Prevention medication

Current treatment protocols recommend prevention medications such as an inhaled corticosteroid, which helps to suppress inflammation and reduces the swelling of the lining of the airways, in anyone who has frequent (greater than twice a week) need of relievers or who has severe symptoms. If symptoms persist, additional preventive drugs are added until the asthma is controlled. With the proper use of prevention drugs, asthmatics can avoid the complications that result from overuse of relief medications.

Asthmatics sometimes stop taking their preventive medication when they feel fine and have no problems breathing. This often results in further attacks, and no long-term improvement.

Preventive agents include the following.

• Inhaled glucocorticoids (fluticasone, budesonide, beclomethasone, mometasone, flunisolide, and triamcinolone).
• Leukotriene modifiers (montelukast, zafirlukast, pranlukast, and zileuton).
• Mast cell stabilizers (cromoglicate (cromolyn), and nedocromil).
• Antimuscarinics/anticholinergics (ipratropium, oxitropium), which have a mixed reliever and preventer effect. (These are rarely used in preventive treatment of asthma, except in patients who do not tolerate beta-2-agonists.)
• Methylxanthines (theophylline and aminophylline), which are sometimes considered if sufficient control cannot be achieved with inhaled glucocorticoids and long-acting β-agonists alone.
• Antihistamines, often used to treat allergic symptoms that may underlie the chronic inflammation. In more severe cases, hyposensitization (“allergy shots”) may be recommended.
• Omalizumab, an IgE blocker; this can help patients with severe allergic asthma that does not respond to other drugs. However, it is expensive and must be injected.
• Methotrexate is occasionally used in some difficult-to-treat patients.
• If chronic acid indigestion (GERD) contributes to a patient's asthma, it should also be treated, because it may prolong the respiratory problem.

Asthma - Long-acting β₂-agonists

Long-acting bronchodilators (LABD) give a 12-hour effect, and are used to give a smoothed symptomatic effect (used morning and night). While patients report improved symptom control, these drugs do not replace the need for routine preventers, and their slow onset means the short-acting dilators may still be required. In November of 2005, the American FDA released a health advisory[13], alerting the public to findings that show the use of Long-acting β₂-agonists could lead to a worsening of symptoms, and in some cases death.

Currently available long-acting beta₂-adrenoceptor agonists include salmeterol, formoterol, bambuterol, and sustained-release oral albuterol. Combinations of inhaled steroids and long-acting bronchodilators are becoming more widespread; the most common combination currently in use is fluticasone/salmeterol (Advair in the United States, and Seretide in the UK).

Asthma - Emergency treatment

When an asthma attack is unresponsive to a patient's usual medication, other treatments are available to the physician or hospital:^[14]

• oxygen to alleviate the hypoxia (but not the asthma per se) that results from extreme asthma attacks;
• nebulized salbutamol (a short-acting beta-2-agonist), often combined with ipratropium (an anticholinergic);
• systemic steroids, oral or intravenous (prednisone, prednisolone, methylprednisolone, dexamethasone, or hydrocortisone)
• other bronchodilators that are occasionally effective when the usual drugs fail:
  • nonspecific beta-agonists, injected or inhaled (epinephrine, isoetharine, isoproterenol, metaproterenol);
  • anticholinergics, IV or nebulized, with systemic effects (glycopyrrolate, atropine);
  • methylxanthines (theophylline, aminophylline);
  • inhalation anesthetics that have a bronchodilatory effect (isoflurane, halothane, enflurane);
  • the dissociative anesthetic ketamine, often used in endotracheal tube induction
  • magnesium sulfate, intravenous; and
• intubation and mechanical ventilation, for patients in or approaching respiratory arrest.

Asthma - Alternative medicine

Many asthmatics, like those who suffer from other chronic disorders, use alternative treatments; surveys show that roughly 50% of asthma patients use some form of unconventional therapy.^{[15] [16]} There are little data to support the effectiveness of most of these therapies. A Cochrane systematic review of acupuncture for asthma found no evidence of efficacy.^[17] A similar review of air ionisers found no evidence that they improve asthma symptoms or benefit lung function; this applied equally to positive and negative ion generators.^[18] A study of “manual therapies” for asthma, including osteopathic, chiropractic, physiotherapeutic and respiratory therapeutic maneuvers, found no evidence to support their use in treating asthma;^[19] these maneuvers include various osteopathic and chiropractic techniques to “increase movement in the rib cage and the spine to try and improve the working of the lungs and circulation”; chest tapping, shaking, vibration, and the use of “postures to help shift and cough up phlegm.” On the other hand, one meta-analysis found that homeopathy has a potentially mild benefit in reducing symptom intensity;^[20] however, the number of patients involved in the analysis was small, and subsequent studies have not supported this finding.^[21] Several small trials have suggested some benefit from various yoga practices, ranging from integrated yoga programs^[22]—“yogasanas, Pranayama, meditation, and kriyas”—to sahaja yoga^[23], a form of meditation. A randomized, controlled trial of just 39 patients suggested that the Buteyko method may moderately reduce the need for beta-agonists among asthmatics, but found no objective improvement in lung function.^[24] See also Complementary and alternative medicine.

Adapted from the Wikipedia article "Treatment", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki