Controlling Asthma: Diagnosing, Drugs

by Food and Drug Administration (FDA)

(Page 2 of 2)

Diagnosing Asthma

The diagnosis of asthma is based on repeated, careful measurements of how efficiently the patient can force air out of the lungs and on a thorough medical history and laboratory tests to find out what triggers the patient's acute attacks.

People with asthma react to external irritants in a way that non-asthmatics don't. Many, but not all, asthmatics have allergies that cause their bodies to produce an abnormal array of chemicals in response to environmental allergens. In that sense, asthma is akin to pollen allergies, hives, and eczema. But in asthma, the allergic reaction contributes to inflammation of the airways rather than of skin, eyes, or nose and throat. An acute asthma attack may come on rapidly after exposure to an irritant or develop slowly over several days or weeks, which can complicate the job of identifying a patient's asthma triggers.

Which drugs asthma patients need, when to use them, and how much to use depend largely on the character of their illness, as shown by the degree of breathing impairment and the frequency and severity of acute attacks. Asthma experts agree, however, that the first line of defense is avoidance of whatever brings on an acute asthma episode. For many patients triggers — there are often more than one — are likely to be identified as common allergens or air pollutants. In some asthmatics, attacks can be brought on by strenuous exercise, exposure to cold outdoor air, industrial or household chemicals (cleaning fluids, for example), and food additives such as sulfites. Influenza or even cold viruses can also trigger asthma episodes. In other cases, the triggers cannot be identified, even after a thorough investigation.

Asthma Drugs

Knowing what provokes an asthma attack is critically important in prevention, but it's often difficult or impractical to avoid contact with triggering irritants. Today, however, physicians can prescribe drugs to lessen the risk of acute attacks after exposure to an offending irritant, as well as halt attacks that can't be prevented.

The drugs used to treat asthma fall into two broad categories: controllers to prevent acute attacks and relievers that check acute symptoms when they occur. Some drugs do both.

In light of mounting evidence that asthma is fundamentally an inflammatory disease, asthma authorities today regard inhaled corticosteroids — marketed under numerous brand names, including Aerobid, Azmacort, Vanceril, Flovent and Pulmicovt — as the most effective agents for controlling airway inflammation and thus preventing acute asthma attacks. Corticosteroids in pill or tablet form (such as Medrol) and in liquid form for children (such as Pediapred and Prelone) are prescribed long-term for some patients with severe asthma, or short-term for patients with a serious asthma episode.

Other inhaled anti-inflammatory controller drugs include Intal (cromolyn sodium), which is useful in preventing asthma brought on by exercise, and Tilade (nedrocromil sodium). A new class of oral anti-inflammatory controller drugs acts by blocking a certain part of the inflammation pathway. This class of "anti-leukotriene" drugs include Zyflo (zileuton), Accolate (zafirlukast) and Singulair (montelukast).

Bronchodilators work to help open the breathing tubes (bronchi), but do not treat the underlying inflammation. There are both short-acting and long-acting bronchodilators. Long-acting inhaled bronchodilators, such as Serevent (salmeterol), and long-acting oral bronchodilators, such as Alupent (metaproterenol), Proventil (albuterol sulfate), Theo-24 (theophylline anhydrous), and many others, are often used in conjunction with anti-inflammatory agents to control symptoms. They don't provide immediate relief of symptoms, but their preventive action persists for many hours, which makes them useful in controlling attacks that might occur during hours of sleep.

Drugs to bring quick relief in acute asthma attacks are chiefly short-acting inhaled bronchodilators that act rapidly but for a relatively brief time to relax bronchial constriction. There are many short-acting bronchodilators to choose from, including Alupent or Metaprel (metaproterenol), Brethaire (terbutaline), and Ventolin or Proventil (albuterol). Although these drugs are effective in treating asthma, there is some controversy about their safety, especially when they are overused. Scientific debate makes it clear, however, that an increasing need for inhaled bronchodilators, or a decreasing response to each dose, is a signal that the patient's asthma is not being adequately controlled. Patients who have an increasing need for short-acting inhaled bronchodilators should be reevaluated promptly by their physicians.

Both prescription and over-the-counter (OTC) short-acting bronchodilators are available. Like the prescription drugs, the OTC drugs act only to provide symptom and relief, and they are generally effective for a shorter period. They may be useful, therefore, as temporary treatment for mild asthma attacks. Ready availability in drugstores makes the OTC products potentially helpful as a "stopgap" for patients who do not have their prescription medication at hand when an asthma attack occurs. More importantly, patients who use OTC inhalers should still seek advice from a health professional about the long-term treatment of their asthma.

The key to effective, long-term treatment of asthma is finding the drugs and dosage plan most effective in dealing with or preventing acute episodes. But effective treatment depends as well on the patient and the care-giver knowing what the various anti-asthma drugs do, when and in what amount each drug should be used, when a change in symptoms or in the response to a particular drug requires a call or visit to the physician, and when to get emergency help. Physicians who specialize in treating asthmatics go over these points in detail as part of an overall treatment plan designed and, as necessary, adjusted to meet the needs of each individual patient.

A cure for asthma is judged by experts to be still a far-off possibility. But the majority of asthma sufferers can lead essentially normal, symptom-free lives by understanding and sticking to a well-planned strategy to keep clear of asthma triggers and to use the right drugs in the right way.

It isn't easy, but it works.

About the Author

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FDA is A United States government body that oversees medical devices, including contact lenses, intraocular lenses, excimer lasers and eyedrops. In the US, these products must be approved by the FDA before they can be marketed.