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Childhood Asthma

Asthma Medications (Preventers)

This section will provide information on preventer medications used in the treatment of asthma.

Note: All medications have a commercial name, and a chemical name. Generic products often use the chemical name. In this site, drugs' chemical names are given in brackets.

Disclaimer: No attempt has been made to list all asthma medications — in general, preference has been given to preparations more commonly used in the Ottawa area.

Tell Me More About Preventer Medications

There are two types of preventer (or anti-inflammatory) medications for asthma. They are the steroid-type preventer medications, and the non-steroid-type preventer medications.

Steroid-Type Preventer Medications

Steroids act directly on the inflammatory cells that cause asthmatic reactions in the lungs. They are the most consistently-effective preventer medications used to treat asthma. The steroid medications used in asthma treatment are different from the anabolic steroids that have been mis-used by athletes, for example, in the Olympics. Steroid medications used for long-term prevention of asthma attacks are almost always given by inhaler. During asthma attacks, steroids given by pill or liquid are used by many doctors to prevent worsening of a severe attack. A few, very severe, asthmatics, need to take oral (pill or syrup) steroid medications on a regular basis.

Inhaled Steroids

Inhaled steroids are designed to go directly to where they're needed (the lungs), with extremely little of the drug reaching the rest of the body. This lets inhaled steroids act as extremely effective preventer-type medications, while markedly reducing the risk of steroid-type side effects. Inhaled steroids are used to prevent asthma attacks, and improve overall asthma control. Because inhaled steroids usually take 1-6 weeks to start working, inhaled steroids generally work best when taken on a regular basis, long-term, using them for a season at a time (or longer). Because inhaled steroids begin working relatively slowly, if your child is started on an inhaled steroid and isn't better after a couple of weeks, you shouldn't get discouraged. Obviously, if during this time, your child gets worse, you should notify your doctor. Inhaled steroids available in Canada include Alvesco® (Ciclesonide), Pulmicort® (Budesonide), FloVent® (Fluticasone), Asmanex® (Mometasone), and QVAR™, (Beclomethasone-HFA). Inhaled steroids are available, depending on the medication, as puffers (Metered-Dose Inhalers), dry powder inhalers including the Diskus®, Turbuhalers®, and Twisthaler®, and for use in nebulizers. Inhaled steroids should be taken every day, even when your child doesn’t have asthma symptoms, during the season(s) when your child is at risk for asthma symptoms or attacks, in order to prevent these events from occurring. Some doctors recommend that when asthma symptoms or peak flows show signs of steady worsening, the inhaled steroid dose should be doubled or tripled. Studies have not shown that doubling the dose during attacks is generally effective. There are studies in adults showing that quadrupling the dose during attacks is effective. However, during a severe asthma attack, oral steroids are recommended to prevent worsening of the severe asthma attack.

Several inhalers containing a combination of inhaled steroid and long-acting Beta-2 Agonist are available in Canada. A long-acting Beta-2 Agonist can be useful for reducing asthma symptoms in people who still have symptoms despite appropriate use of an inhaled steroid. One major advantage of a combination inhaled steroid and long-acting Beta-2 Agonist inhaler is convenience, for people requiring both an inhaled steroid and a long-acting Beta-2 agonist. In addition, for adolescents, the combination product will prevent them from using only the Beta-2 agonist (which provides fairly rapid symptom relief) but will instead ensure that they also receive the inhaled steroid, to provide an anti-inflammatory, preventer effect. FloVent® (Fluticasone), combined with a long-acting Beta-2 Agonist, Salmeterol (Serevent®), is available in a single inhaler, called Advair(TM). Advair(TM) is licensed in Canada for individuals 4 years of age and older. It is available as both a Diskus inhaler® and as a metered-dose inhaler. Pulmicort® (budesonide) combined with a long-acting Beta-2 Agonist, Oxeze® (formoterol) is available in a single inhaler, called Symbicort®. It's licensed in Canada for individuals 12 years of age and older, and is available in a turbuhaler®. Asmanex® (Mometasone) combined with a long-acting Beta-2 Agonist formoterol is available in a single inhaler called Zenhale®. It’s licensed in Canada for individuals 12 years of age and older, and is available in a metered-dose inhaler.


Most children using inhaled steroids experience no side effects at all.
  • A few people have dry mouth or throat irritation. This is usually minor.
  • Inhaled steroids can cause Thrush in the mouth (little white patches, caused by a yeast infection). If this happens, it is usually treated with a special anti-yeast antibiotic. Thrush can be prevented by:
    • rinsing the mouth with some water (and, ideally, spitting the water out) after using the inhaled steroid inhaler;
    • using a spacer device (like the Aerochamber® or the ACE® spacer), so the heavier medicine particles released by the inhaler land in the spacer, rather than in the mouth.
  • Very, very, rarely, inhaled steroids can cause a hoarse voice. If your child develops a hoarse voice for no good reason (such as a cold), you should let your doctor know, because the hoarseness can be important.
  • The effect of inhaled steroids on growth are difficult to measure, because severe, uncontrolled asthma affects growth. Children on inhaled steroids should have their growth carefully monitored. One recent study suggests that inhaled steroids may cause a short-term decrease in growth. As children with asthma often have catch-up growth in puberty, it is not known whether this leads a decrease in the final adult height. Many children on inhaled steroids grow just fine. A few actually grow better on inhaled steroids — because their asthma comes under better control.

  • Standard doses of inhaled steroids may cause minor changes in the balance of natural steroid hormones which are produced by the body. This does not seem to be of any clinical significance.

  • Very high doses of inhaled steroids (or inhaled steroid-long-acting Beta-2 agonist combination inhalers) may cause the adrenal glands to work less well. The adrenal glands naturally produce steroids, and produce higher levels during periods of stress, such as during infections or surgery. When the adrenal glands work less well, this is known as adrenal suppression. Symptoms of adrenal suppression include fatigue, abdominal pain, mood changes, low blood pressure, and/or low blood sugar. Many, but not all, children with adrenal suppression due to steroids also have reduced growth. If you are worried that your child could have adrenal suppression, you can ask your doctor for a blood test. The blood test, called a serum cortisol, needs to be done first thing in the morning (before 8:30 am), but doesn’t need to be done fasting. Children on high doses of inhaled steroids or prolonged (over 2-week) treatment with steroids by mouth should have a morning cortisol test once or twice a year. 

  • Children with severe asthma may frequently need Oral Steroids. By reducing the severity of asthma, inhaled steroids generally reduce the need for oral steroids. Studies have shown that being on an inhaled steroid all year long has less effect on natural steroid hormone balance than 4 courses of oral (or intravenous) steroids in a year. Note that if your child is on inhaled steroids and your doctor recommends a course of oral steroid to control an asthma attack, your child should take the oral steroid because it can prevent a severe asthma attack.

  • Some research has suggested that the risk of glaucoma (fluid build-up, causing increased pressure in the eye) may be increased in elderly people using high doses of inhaled steroids for long periods of time. Glaucoma is much more common in the elderly, and extremely rare in children. There are no studies available to suggest that inhaled steroids increase the risk of glaucoma in children, and this problem has not been seen in children on inhaled steroids in the Ottawa region. Canadian studies have shown that cataracts, which can occur from long term use of Oral steroids, do not occur with long term use of inhaled steroids. Canadian guidelines have been issued recommending that people with asthma who need inhaled steroids should continue using them. Obviously, if you are concerned that your child has an eye problem or difficulties seeing (whether or not they are receiving inhaled steroids), you should have your child seen by an eye specialist, and have the Intra-Ocular Pressure recorded.

Oral Steroids

Steroids can be given by mouth or, in a hospital setting, injected (either through an intravenous, or into the muscle). Steroids, when given in such ways, powerfully reduce inflammation, and are effective in helping control severe asthma attacks. Oral steroids are usually given for 3-7 day periods; when used for a week or more, the dose is usually slowly tapered down over a varying period of time. Oral steroids rarely have serious side effects when given for 3-7 day periods.

In a few, very severe asthmatics, oral steroids are used for months at a time (or even longer). This should be done under the careful supervision of a doctor. When oral steroids are used for months at a time (or longer), there is a potential for a number of serious side effects.

In Canada, commonly-used oral steroids include Prednisone, PediaPred® (Prednisolone), and Decadron® (Dexamethasone).

  • When used for short (3-7 day) periods, oral steroids can cause mood changes, increased appetite, and weight gain. Serious side effects are uncommon.
  • When used for long periods (many months or more), oral steroids can cause reduced growth, thinning of the bones, eye problems, high blood pressure, difficulties dealing with stresses (like surgery) known as adrenal suppression, reduced ability to handle infections (especially chickenpox), and weight gain. Because of the potential for these kinds of side effects, patients on long-term treatment with oral steroids are monitored closely by a doctor.

Non-Steroid Preventer Medications

Non-steroid preventer medications interfere with either certain inflammatory cells in the lungs, or with the chemicals these cells release. This reduces lung inflammation, improving asthma control and preventing asthma attacks. There is one non-steroid preventer medication available in Canada: the anti-leukotriene medication Montelukast.

Note: Doctors sometimes call Aspirin® and Aspirin®-like drugs (like Motrin®) Non-Steroidal Anti-Inflammatory Drugs (or NSAIDs). NSAIDs are different from the Non-Steroid anti-inflammatory anti-asthma drugs discussed in this site. NSAIDs can actually worsen asthma in some asthmatics.

Anti-Leukotriene Medications

Leukotrienes are chemicals released by inflammatory cells in the lungs, that play a key role in inflammation. Anti-leukotriene medications work by blocking the action of these leukotrienes. In Canada, there is one anti-leukotriene medication available: Singulair™ (or Montelukast). It is normally given on a long-term, regular basis to prevent asthma attacks and improve asthma control, although there is some evidence it may be helpful if used during colds.

Given alone, they reduce asthma symptoms, exercise-induced asthma, and the frequency of asthma attacks by 30-50%. This may be adequate for patients with mild asthma, but patients with moderate or severe asthma (such as patients with attacks severe enough to need visits to an Emergency Room or admission(s) to hospital) will generally have better asthma control if they take an inhaled steroid.

An anti-leukotriene medication may be helpful when combined with an inhaled steroid. Combined treatment, with an anti-leukotriene medication and an inhaled steroid may result in fewer symptoms than using the inhaled steroid alone, and it may allow the doctor to reduce the amount of inhaled steroid needed by the child. In a child who needs an inhaled steroid to prevent severe asthma attacks, decreasing the inhaled steroid dose too much (or stopping the inhaled steroid) could put the child at risk for a severe attack. If your child is taking an inhaled steroid and your doctor adds an anti-leukotriene medication, the inhaled steroid should not be stopped abruptly, and the dose should not be reduced without your doctor's advice.

These medications are given in pill-form or a sprinkle that can be sprinkled on apple sauce, rather than by inhaler. This is convenient for many people. These medications take about 1-7 days to start working, and reach maximum effect in 3 weeks. This means that if your child is started on Singulair™ and isn't better after a day or two, you shouldn't get discouraged. Obviously, if during this time, your child gets worse, you should notify your doctor.

In Canada, Singulair(™) is licensed for use in children 2 years of age, and older. It is given as a single dose, at bedtime.

  • Anti-leukotriene medications are used as preventer medications, on a long-term, regular basis.
  • Anti-leukotriene medications may be used on their own, or together with an inhaled steroid.
  • In general, side effects with are very rare. These medications occasionally cause headaches and stomach aches.
  • Occasionally, children can develop behavior problems, such as mood changes, irritability, or nightmares, and adolescents can develop depression. If your child develops these symptoms on Singulair™, you should speak immediately to your doctor about stopping this medication. The symptom(s) go away when the medication is stopped.
  • Very rarely, patients on these medications have developed liver problems.
  • There had previously been a concern about patients very rarely developing a rare disease called Churg Strauss Syndrome. Churg Strauss Syndrome involves inflammation of blood vessels, abnormal shadows on the chest X-ray, and heart problems. Recent data does not suggest a link between anti-leukotriene medications and Churg Strauss Syndrome.
    Please read our Asthma Devices Page for more information about asthma medications.


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