Medications to Treat Your Asthma

In a general sense, asthma medications have two goals: to prevent or reverse contraction of the bronchial muscles, and to reduce inflammation of the walls of the bronchial tubes (see Figure 4). Bronchodilators and anti-inflammatory medications work on very different timetables. The muscles that surround the breathing tubes can be made to contract in minutes — as you know if you suddenly have asthma symptoms after running to catch the bus on a cold winter day — and likewise can be made to relax, with bronchodilator medication, within minutes. Inflammation of the bronchial tubes comes on more slowly and takes hours or days to respond to anti-inflammatory medications. Bronchodilators can be used intermittently for fast relief of symptoms, while anti-inflammatory medications need to be taken regularly over many days, and perhaps indefinitely. When you stop taking an anti-inflammatory medication, asthmatic inflammation of the bronchial tubes will recur within two to four weeks.

Figure 4: How medications treat asthma   How medications treat asthma - A   When you inhale a bronchodilator or controller medication, the drug acts directly on your bronchial tubes (A). (Medications taken as tablets reach your lungs indirectly, through the bloodstream.) Quick relievers act as bronchodilators, relaxing muscles in the bronchial tubes so that the restricted airway passage reopens — often within minutes (B). Controllers may work to relax the bronchial muscles, reduce the cells and molecules involved in inflammation, or both (C).   How medications treat asthma - B - Bronchodilators     How medications treat asthma - C - Controllers

Asthma medications have come to be categorized as quick relievers and controllers. These terms reflect how the medications are meant to be used, rather than emphasizing the mechanism of airway narrowing they target. This division of asthma medications came about because some newer asthma medications seem to have both bronchodilator and anti-inflammatory effects, and because some newer bronchodilators are prescribed for daily use to prevent asthma symptoms.

For all but the mildest asthma, a good asthma management plan involves taking both types of medicine. All of the controller medications — not just the anti-inflammatory medications — are taken every day, whether you have symptoms or not. Quick relievers can be taken whenever you have uncomfortable symptoms of asthma. Virtually everyone with asthma should have a quick reliever handy at all times, just in case.

Quick relievers

When asthma causes shortness of breath, tightness in the chest, and troublesome coughing and wheezing, you want quick relief. At such times, fast-acting bronchodilators are the best option (see Table 1). These medicines relieve symptoms quickly by relaxing the muscles that surround the bronchial tubes and enabling the tubes to open wider.

Inhaled quick-acting bronchodilators begin to work within five minutes and continue providing relief for about four to six hours. You can also use your quick reliever 10–15 minutes before a predictable exposure to something that typically sets off your asthma, such as exercise or the cat at your neighbor’s house. Quick relievers can often prevent tightening of the bronchial tubes that would otherwise occur. If your asthma symptoms are mild and infrequent, a quick reliever may be the only medication you need.

Beta-2 agonist bronchodilators

The most effective bronchodilators are known as beta-agonist medications because they work by stimulating molecular targets known as beta receptors. The first medication with beta-agonist properties, adrenaline (now more commonly called epinephrine), was developed in 1901. Years ago, a severe asthma attack was often treated with a shot of adrenaline. The treatment was effective but had significant side effects, including a racing, pounding heart; jitteriness; headache; and an increase in blood pressure. Epinephrine treatment is still occasionally used today in emergency situations. Inhaled epinephrine is also still available, as the active ingredient in Primatene Mist, a bronchodilator sold over the counter. Such over-the-counter bronchodilators are less effective, last for a shorter time, and have more side effects than modern prescription bronchodilators.

In 1948, scientists developed a derivative of epinephrine, isoproterenol (Isuprel), which eliminated some of these side effects. If you are old enough and have had asthma long enough, you may remember using an Isuprel Mistometer to relieve your asthma symptoms. However, overusing these bronchodilators to treat asthma attacks, while neglecting to treat the swelling and mucus plugging of the bronchial tubes, can result in disaster: severe asthma attacks and even death.

A major advance in asthma treatment was the development of more selective medications, known as beta-2 agonist bronchodilators, which work quickly, dilate the bronchial tubes effectively, and have fewer unpleasant side effects than the older medicines. The selective beta-2 agonist bronchodilators use a modified form of epinephrine and related chemicals to minimize cardiac side effects (caused by stimulation of beta-1 receptors) while maintaining bronchodilating effects (by stimulating beta-2 receptors).

Side effects of beta-2 agonists, if they occur, can include heart pounding, a jittery feeling, and shakiness. The standard dose in adults is two inhalations, or puffs. Fortunately, for those adults who are particularly sensitive to side effects, one inhalation — with consequently fewer side effects — may suffice to open the breathing tubes. The medications work for about four to six hours. When they wear off, if you are still having asthma symptoms, you can take another dose (one to two puffs). In an asthma attack, when the bronchial tubes are severely narrowed, you can use your bronchodilator more often to get through a difficult period — as often as every 20 minutes.

Selective beta-2 agonists are available only by prescription. The most widely used is albuterol, available as a generic albuterol inhaler and also sold under the brand names Proventil and Ventolin. Other commonly prescribed beta-2 agonists include metaproterenol (Alupent) and pirbuterol (Maxair). These medications all come in metered-dose inhaler devices small enough to fit in your purse or pocket, so they can be within easy reach whenever you need a puff or two to quiet your coughing or wheezing and restore your breathing to normal.

Using beta-2 agonists. Selective beta-2 agonists are available in tablets and liquid formulations, as well as in forms for inhalation. The inhaled medicine works faster, dilates the bronchial tubes better, and has fewer side effects than the tablet or liquid forms. To be effective, however, quick relievers need to be inhaled deeply into the bronchial tubes, not squirted onto the back of the throat. A holding chamber device known as a spacer can improve medication delivery. If you use a spacer with your regular controller medicine, you can use the same one with your quick reliever. Maxair has a unique breath-activated delivery device, called the Autohaler, which releases a pressurized spray of medication as soon as you begin to breathe in. (For more information on the use of inhalers, see “Types of drug-delivery devices.”)

Contrary to what was once thought — and taught — it is not necessary to use your quick-relief bronchodilator before inhaling your controller medication. In fact, you don’t need to take the quick reliever on any regular schedule. Use it when you need it to get rid of or prevent your asthma symptoms; don’t use it when you don’t have any symptoms.

At a medical visit, your health care provider will probably ask how often you have needed to use your quick-relief bronchodilator. This information is a useful measure of how active your asthma is. With good asthma control, you should need to use your quick-relief bronchodilator infrequently, ideally no more than once or twice a week.

Newer beta-2 agonists. Beta-2 agonist bronchodilators have advanced even further since the 1990s. Long-acting beta-2 agonist bronchodilators, effective for 12 or more hours, are now used as controller medications (see “Controller medications”). Another refinement was the creation of a purified form of albuterol known as levalbuterol (Xopenex). This medication is effective as a bronchodilator but causes slightly fewer side effects than albuterol, particularly jitteriness and heart racing. For most people, the advantages of levalbuterol over albuterol are small and not worth the significantly greater cost. However, in older people with heart disease such as angina or irregular heart rhythms, the lesser degree of heart stimulation caused by levalbuterol may be worth the expense. Levalbuterol is currently available as a liquid for nebulization. A metered-dose inhaler version is expected soon.

Other bronchodilators

For most people with asthma, the inhaled beta-2 agonist bronchodilators provide the best choice for quick relief of symptoms. There are some exceptions, however. Another type of bronchodilator may be appropriate in the following situations:

• You have serious and unstable heart disease. Under this circumstance, even a little extra stimulation of the heart might cause complications.

• You are taking a medication that might adversely interact with beta-agonists, such as a monoamine oxidase (MAO) inhibitors. Examples of MAO inhibitors include the rarely used antidepressants phenelzine (Nardil) and tranylcypromine (Parnate), and the anti-Parkinsonian medication selegiline (Eldepryl).

In these cases, the bronchodilator ipratropium (Atrovent), an anticholinergic medicine, may be used. Normally ipratropium is used for the treatment of emphysema and chronic bronchitis, not for asthma. Compared with inhaled beta-2 agonist bronchodilators, it is weaker and slower. It takes 10–15 minutes to begin working, compared with fewer than five minutes for the fast-acting bronchodilators.

Another medication, theophylline, was the mainstay of bronchodilator therapy in the mid-1980s. Many people still rely on sustained-release theophylline in capsule or tablet form as a controller medication (see “Controller medications”). But theophylline has fallen from favor in the treatment of asthma, in part because of its frequent side effects and risk for toxicity, in part because of the availability now of better long-acting bronchodilators. Theophylline may cause nausea, diarrhea, and headache, as well as jitteriness and shakiness. More serious, if you take too large a dose of theophylline, there is a risk for seizures and irregular heart rhythms, which can be fatal. Theophylline overdoses have been responsible for intensive care unit admissions and even deaths. Many physicians consider it the most dangerous asthma medication around. (If you have been taking theophylline for years, you might want to consider switching to one of the newer long-acting inhaled bronchodilators. Talk with your doctor about options.)

Controller medications

People know that it’s possible to prevent tooth decay by brushing once or twice a day and going for regular dental checkups. In the same way, asthma treatments taken once or twice each day are generally effective in controlling asthma symptoms and preventing severe, potentially dangerous asthma attacks. And your breathing is at least as important as cavity-free teeth!

There are two ways in which controller medications work. Those with anti-inflammatory properties reduce the swelling and inflammation of the bronchial tubes, making the airways less sensitive to asthma triggers. Those that function as long-acting bronchodilators cause the bronchial muscles to relax throughout the day, helping to prevent muscle spasms that narrow the bronchial tubes. Some controller medications achieve both effects.

Some people with asthma need to take a controller medicine only during allergy season or following a respiratory infection. Most people with persistent asthma, however, need to take preventive medicines every day.

Controller medications help you feel better over time. In most cases, within two weeks or less you will have fewer asthma symptoms and find yourself less sensitive to asthma triggers and attacks. You will feel as though your asthma is going away, and you will be pleased at how rarely you need your quick-relief bronchodilator.

Inhaled corticosteroids

Inhaled corticosteroids (see Table 2), usually referred to simply as inhaled steroids, have consistently proved to be the most effective type of controller medication for asthma. Although some forms of steroid medication can have harmful effects because they reach many parts of the body (see “Not all steroids are alike”), inhaled steroids are safe at the usual dosages because only minuscule amounts of medication enter the bloodstream. Like a steroid skin cream rubbed on a rash, for the most part an inhaled steroid medicine exerts its effect only where it’s applied — in this case, directly to the airways, where it reduces inflammation.

Inhaled steroids take longer to work than your quick-acting bronchodilator. It takes one to two weeks of regular use for an inhaled steroid to reduce the swelling and irritation of the bronchial tubes. At that point, you will probably experience fewer symptoms and find that you need to use your bronchodilator less frequently. Another difference between the medications is how often you need them. You use a quick-acting bronchodilator only when your symptoms act up. By contrast, you take your inhaled steroid every day, whether you have symptoms or not.

Regular use of inhaled steroids in asthma is known to improve a person’s sense of well-being, reduce asthma symptoms, increase breathing capacity, and reduce the risk for asthma attacks. In fact, one study found that people using inhaled steroids were only half as likely to be hospitalized for a severe asthma attack as those not taking these medications.

For several decades, only three inhaled steroids were available to treat asthma: beclomethasone (Beclovent, Vanceril), triamcinolone (Azmacort), and flunisolide (Aerobid). Since the 1990s, new steroids have been introduced, each with distinctive and potentially advantageous features: fluticasone (Flovent), budesonide (Pulmicort), and beclomethasone with a non-CFC propellant (QVAR).

Your doctor will decide how much inhaled steroid to give you, which in turn determines how many puffs or inhalations you take every day. If your doctor prescribes your inhaled steroid to be taken twice a day, that usually means morning and evening. Budesonide has been approved for once-daily dosing in mild, well-controlled asthma.

The most common side effects of inhaled steroids are a dry, irritated throat and a hoarse voice. A minor yeast infection of the mouth and throat called thrush or oral candidiasis can develop, requiring treatment with antifungal mouthwash, lozenges, or tablets. You can avoid thrush by rinsing your mouth after each use of the steroid inhaler and by using a spacer with steroids that are delivered by metered-dose inhaler.

Inhaled steroids can cause more serious long-term side effects if they are absorbed into the bloodstream. This can happen in two ways. You might swallow the medication residue in your mouth, so it gets into your stomach and is then absorbed into the bloodstream. (Again, you can avoid this by rinsing your mouth after each use of the inhaler and using spacers with steroids delivered by metered-dose inhaler.) In addition, some of the medication is absorbed by the blood vessels in the bronchial tubes and transported into the bloodstream. When low doses of the steroids are used, this is not a problem. But if you use high doses of inhaled steroids for a long time, after several months you begin to be at risk, to a slight degree, for side effects more typical of systemic steroids. These include an increased risk for glaucoma and cataracts, skin bruising, and bone loss with increased risk for osteoporosis.

Systemic corticosteroids

Steroid medicines taken as tablets or by injection are used when asthma is unusually severe, or during a severe flare-up, and are the most powerful medicines available to treat asthma (see Table 3). But systemic steroids are often thought of as a double-edged sword: powerful both in their benefits and, over time, in their undesirable side effects.

Typically, steroid tablets are given for a few days, up to two or three weeks, for an asthmatic crisis, when no other medicine or combination of medicines can relieve symptoms or improve breathing capacity. At such times, they are given in relatively large doses: 10–60 milligrams (mg) per day and more.

In very rare instances, only steroid tablets will work to control symptoms in a person with severe persistent asthma. This is known as steroid-dependent asthma. If you have steroid-dependent asthma, ask to see an asthma specialist. It may be possible to find an alternative, safer way to control your asthma.

Long-acting bronchodilators

Like quick-acting bronchodilators (see Table 1), long-acting bronchodilators (see Table 4) help keep the muscles around your bronchial tubes relaxed. Not all begin to work as fast as the quick-acting bronchodilators, but their effects last longer — 12 hours or more. When taken once or twice daily, the long-acting bronchodilators can provide effective asthma control, especially when used together with anti-inflammatory medications.

The first of the long-acting inhaled beta-2 agonist bronchodilators, salmeterol (Serevent), was introduced in 1995. When used together with an anti-inflammatory medication, it proved to be a highly successful controller medication. Several studies have shown that when asthma symptoms are poorly controlled, adding a long-acting inhaled beta-2 agonist (salmeterol or formoterol) to a regimen of inhaled steroids works better than taking higher doses of the inhaled steroids alone. Many people with difficult-to-control asthma find that by combining a long-acting inhaled beta-agonist and an inhaled steroid, they can take lower doses of inhaled steroids than they would otherwise need, thus avoiding the possible side effects of high-dose inhaled steroids.

Salmeterol (Serevent). Doctors usually prescribe salmeterol to be taken twice daily, although occasionally people who have asthma symptoms only during the daytime may take it once a day in the morning, and people whose asthma bothers them exclusively at night may take it once a day in the evening. Salmeterol begins to work about 15–20 minutes after you inhale it. The morning dose works to prevent asthma symptoms brought on by exercise at any time throughout the day; the evening dose works as a bronchodilator all night long and may help prevent nighttime awakenings due to asthma. Side effects (jitteriness, tremor, racing heart, muscle cramping) tend to be minimal, and many people do not experience them at all. The medication is now available only in a dry-powder inhaler device called the Diskus (see “Dry-powder inhalers”); the metered-dose inhaler formulation has been discontinued.

To safeguard your health, always use salmeterol in combination with an anti-inflammatory medication: an inhaled steroid, a leukotriene blocker, or a mast cell stabilizer. Some evidence suggests that a small number of people — particularly African Americans — who use salmeterol as their only controller medication, without anti-inflammatory therapy as well, are more at risk for severe asthma attacks and even death. It is unclear why. One theory is that salmeterol works so well at relaxing the bronchial tubes that people may find themselves falsely lulled into a sense of well-being and then expose themselves to an asthma trigger. For example, you might spend the day playing with a new kitten or doing yard work while your bronchial tubes swell and fill with mucus — leading to a full-blown asthma attack and difficulty breathing.

Concerns about the safety of salmeterol led the FDA to require a “black box” warning — its strongest — in the package insert. As this publication went to press, it appeared that the FDA might be preparing to reevaluate the evidence about salmeterol after one of the agency’s drug reviewers raised new safety concerns. Until the FDA provides further guidance, many doctors are continuing to prescribe salmeterol in combination with anti-inflammatory medications, as it is enormously helpful for many people with moderate and severe persistent asthma.

Formoterol (Foradil). Like salmeterol, formoterol is a selective beta-2 agonist that keeps bronchial muscles relaxed for at least 12 hours with minimal side effects. It too should be used in combination with an anti-inflammatory medication. Formoterol differs from salmeterol in that it begins to act very rapidly — often within three to five minutes. Another distinguishing feature is its unique dry-powder inhaler device, called an Aerolizer, which delivers the medicine to your bronchial tubes. The Aerolizer is a single-dose device: Each dose of the medicine has to be loaded individually.

Advair. This medication combines salmeterol with an anti-inflammatory steroid, fluticasone. Advair is available in a single dry-powder inhaler, the Diskus. This combination medicine is prescribed as one inhalation twice daily. It is convenient and highly effective: With one device, you can simultaneously treat airway narrowing caused by bronchial muscle contraction and inflammation. One disadvantage is that the doses of the two medicines are linked in a fixed combination and cannot be adjusted independently. For example, if you want to double your dose of inhaled steroids by taking two inhalations from your Advair Diskus, you will also get twice as much salmeterol, which is more than the recommended dose. To overcome this drawback, Advair has been made available with three different dosage strengths of the fluticasone component.

Other long-acting bronchodilators. Theophylline and albuterol, two medications normally used for quick relief of symptoms, are also available in slow-release preparations that are sometimes used for long-acting bronchodilation. Theophylline is available in generic slow-release preparations and is sold under such brand names as Uniphyl, Theo-24, and Theolair. A number of people with asthma have taken slow-release theophylline for many years with good results. If you are comfortable with the medication, continue it, but you may want to talk with your physician about new alternatives. Slow-release albuterol (Ventolin, Volmax, others) is not as effective as the inhaled version at opening bronchial tubes, and carries a greater risk for side effects.

An ultra-long-acting bronchodilator called tiotropium (Spiriva), which belongs to the same class as ipratropium (see “Other bronchodilators”), has become available for the treatment of emphysema and chronic bronchitis. Tiotropium is used once daily, providing bronchodilation for a remarkable 24 hours. The dry-powder inhalation device, called a Handihaler, aerosolizes one capsule of medication at a time. Tiotropium is not as effective as the long-acting inhaled beta-2 agonists at providing bronchodilation in asthma; for that reason, like ipratropium, it is recommended only rarely for use in asthma.

Mast cell stabilizers

Whereas inhaled steroids target various aspects of inflammation, mast cell stabilizers (see Table 5) work specifically on a particular type of allergy cell. These medications prevent mast cells from breaking open and releasing chemicals like histamine that contribute to inflammation. The only mast cell stabilizer currently available to treat asthma is cromolyn (Intal). (Another mast cell stabilizer, nedocromil (Tilade), has been withdrawn from the market.) If the medication is in your system, it interrupts the allergic response that would typically result when you encounter an allergen. Cromolyn is purely preventive, however: Taking the drug after you have already begun coughing and wheezing from an exposure will not relieve your symptoms.

The great appeal of cromolyn is that it is virtually free of side effects. And one particular use is worth mentioning: Cromolyn effectively blocks exercise-induced bronchial narrowing when taken as a single dose 15–20 minutes before exercise. Although quick-acting bronchodilators may also be used for this purpose, cromolyn offers an alternative for people who are especially susceptible to the jittery side effects of quick-acting bronchodilators, such as albuterol. It can also be taken in addition to albuterol or other quick-acting bronchodilators if they are not enough to prevent exercise-induced asthma attacks.

However, cromolyn has a number of shortcomings. First, it must be administered four times daily to be effective as a controller medication. Second, it is only modestly effective, especially when compared with inhaled steroids; it does not provide protection against severe asthma flare-ups as reliably as inhaled steroids. Third, increasing the dose does not help during asthma attacks.

Leukotriene blockers

A family of preventive medications, called leukotriene blockers (see Table 6), has been available since the mid-1990s. Leukotriene blockers represent a real innovation in asthma medications. Leukotrienes are chemicals that contribute both to asthmatic inflammation and bronchial muscle contraction. Leukotriene blockers are available as tablets (and as sprinkles for very young children), can be taken once or twice daily, and generally have no side effects. Their safety is emphasized by the approval for use of one of the leukotriene blockers in children as young as 12 months.

After years of scientific research into the structure and function of leukotrienes and the importance of their role in asthma, zafirlukast (Accolate) was introduced as the first medication that blocks the action of leukotrienes in the same way that antihistamines block the effects of histamine. Since then two more leukotriene blockers have been introduced: montelukast (Singulair) and zileuton (Zyflo). Zafirlukast and montelukast block the action of leukotrienes after the body makes them; zileuton inhibits the formation of leukotrienes in the first place. Zileuton, which needed to be taken four times a day and had a small potential for causing liver inflammation, was withdrawn from the market in late 2003.

For some people, leukotriene blockers work very well — lessening symptoms, improving breathing capacity, and reducing the frequency of asthma attacks. For mild asthma, they may be the only preventive medication needed. They can also be used in combination with other controller medicines for more severe disease. But these medications do not seem to help everyone with asthma; as many as 4 of 10 people derive little or no benefit. One particular indication for using a leukotriene blocker: People with aspirin-sensitive asthma (see “Medication triggers”) make relatively large amounts of leukotrienes and are particularly likely to benefit from leukotriene blockers.

Anti-IgE antibodies

Imagine if you could design a molecule that would bind to the allergy protein, IgE (see “The allergy connection”), and remove it from the bloodstream so that it would not be available to bind to mast cells and await the arrival of allergens to trigger an allergic response. One asthma medication, omalizumab (Xolair) is just such an anti-IgE antibody: This molecule is specifically designed to bind to IgE molecules in the blood without activating an allergic reaction — essentially damping down the allergic apparatus of asthma (and other atopic diseases).

Omalizumab is administered as an injection once or twice a month (depending on dose). Localized reactions at the injection site have been few, and there are no known generalized side effects. As you might imagine, the cost of the medication is enormous, in the range of $10,000 per year or more, and so the indications for its use have been quite selective. Omalizumab is recommended for people with moderate-to-severe persistent asthma whose symptoms are not well controlled on conventional therapy. In addition, they must have an elevated blood level of IgE protein and demonstrated allergic sensitivity to at least one year-round inhaled allergen. For some (although not all) of the people meeting these criteria, treatment with anti-IgE antibody therapy has helped to improve symptoms, reduce the need for steroids, and prevent asthma attacks.

Types of drug-delivery devices

Different types of devices are used to deliver inhaled medications into the lungs. Inhalers are small pocket-sized containers that enable you to inhale the medication as an aerosolized powder or spray in precisely controlled doses with each inhalation. There are two types of inhalers: metered dose (sometimes used with spacers) and dry powder. The type of inhaler you choose will depend on which drugs you need and how easy the inhaler is for you to use. If you have trouble using an inhaler, your doctor may recommend a nebulizer, a machine that delivers a continuous fine mist of medicine through a mouthpiece or face mask as you breathe normally for several minutes.

Two delivery devices Many people use a metered-dose inhaler (top) for inhaled medications such as bronchodilators and steroids. Another option is a nebulizer (bottom), which allows you to breathe at your own pace while taking the medication.   Metered dose inhaler with spacer   Metered-dose inhaler with spacer   Nebulizer   Nebulizer

Metered-dose inhalers

Traditionally, most inhaled asthma medications have been given by means of a metered-dose inhaler, which consists of a metal canister inside a plastic dispenser. You press down and then release the canister, which delivers a spray containing a set amount of medication.

To use a metered-dose inhaler correctly, you need to inhale the medication deep into your lungs, so that it distributes widely along the bronchial tubes. This can be tricky: The spray is released from the pressurized canister at high speeds, and if you don’t inhale at just the right time, the aerosol spray stays in your mouth or settles on the back of your throat and doesn’t pass into your lower airways. The following three steps may help:

• Start breathing in as soon as you press down on the canister and feel the spray. If you wait too long to inhale, you lose a lot of medication that settles onto your tongue and mouth rather than being drawn into your breathing tubes. On the other hand, if you inhale too soon, before activating the spray, you will not have enough breath left to pull the medicine into the bronchial tubes.

• Breathe in slowly so that the medication has time to disperse to the thousands of bronchial tubes. If you inhale too quickly, the medication reaches only the upper breathing passages. It should take about three or four seconds to pull in a slow, full breath.

• Hold your breath for a few seconds after completing the inhalation. If you breathe out immediately, you will exhale some of the medication. Try to hold your breath for about five seconds before exhaling.

Spacers

These simple devices can make the use of metered-dose inhalers a lot easier and more effective. A spacer is a hollow chamber that attaches to your metered-dose inhaler. In its simplest form, it is a hollow plastic tube that fits onto the mouthpiece of your metered-dose inhaler. You place your mouth on the mouthpiece of the spacer, and instead of spraying the medication directly into your mouth, you spray it into the chamber, where it remains suspended for a few seconds. You inhale the medicine from the other end of the chamber in one or two slow, deep breaths, without any sense of urgency or need for split-second timing in relation to actuating the spray.

Spacers are most useful for people who have difficulty coordinating the hand-breath actions that a metered-dose inhaler requires. They are also useful for anyone taking inhaled steroids delivered by metered-dose inhaler, as the spacer reduces the amount of medication deposited onto the tongue and the back of the throat, thus lessening the chance of developing side effects from swallowing too much of the steroid drug. If you are taking a quick-acting bronchodilator and you are good at inhaling it from a metered-dose inhaler, there is no need to use a spacer, as it provides no added benefit.

Dry-powder inhalers

In the past, the sprays released from metered-dose inhalers have been driven by propellants known as chlorofluorocarbons (CFCs). After CFCs were banned because of their detrimental effect on the atmospheric ozone layer, it became necessary to develop alternative delivery systems. One approach uses an ozone-safe propellant, called hydrofluoroalkane (HFA), in metered-dose inhaler canisters. The other is the introduction of dry-powder inhalers. Instead of generating a pressurized spray, these devices release a fine, micronized powder as you inhale. As such, dry-powder inhalers may be easier to use than metered-dose inhalers because you don’t have to coordinate your breathing with the device; the powder is released automatically when you inhale deeply. Currently available dry-powder devices include the Diskus, Turbuhaler, Handihaler, and Aerolizer, each containing different types of medicines.

Nebulizers

A nebulizer delivers inhaled medicine through a face mask or mouthpiece, allowing you to breathe normally while receiving treatment. The device consists of a chamber containing the drug in liquid form and a compressor pump. Operated either by AC electrical power or by battery, the compressor sends air across the nebulizer chamber that contains the medicine. The stream of air scatters the drug into a fine mist, which passes into the face mask or mouthpiece. You breathe in and out through the mask or mouthpiece for about 10 minutes to obtain the full dose.

An advantage of the nebulizer is that a lot of medicine is reliably delivered to the bronchial tubes in this way. Its major disadvantage is its lack of convenience. Unlike the inhaler, this device cannot readily be carried in your pocket or purse for prompt use at any time.