The main goal of most control drugs is to prevent symptoms from occurring in the first place. In general, anyone with persistent asthma should take a control drug every day. (Read more about children under age 5.)

Some people use control drugs only during times when they are likely to be exposed to one of their asthma triggers, such as a particular season or when staying at a pet owner's house.

The following are the main drugs in this category.

Inhaled steroids

Steroids (also called corticosteroids) are very effective for long-term control when taken daily. They are generally a doctor's first choice for daily medication to treat persistent asthma at all levels of severity. For moderate to severe asthma, they are even more effective when combined with long-acting beta agonists. (See combination therapy, below.) Steroids work by reducing inflammation in the airways. Steroids are generally inhaled using a metered dose inhaler (MDI) device or dry powder inhaler (DPI).

The Food and Drug Administration has approved a corticosteroid (Pulmicort® Respules) for children as young as one year. This drug is administered using a nebulizer, and therefore may be suitable for young children and elderly who can't easily manipulate inhalers and spacers. Steroids are also available as pills, liquids, and other forms, but these are generally used in special cases, such as initial treatment to bring asthma under control or severe persistent asthma that has not been brought under control by other drug treatments.

Examples of other steroids include Beclovent®, Qvar®, and Vanceril® (beclomethasone), Pulmicort® Turbohaler (budesonide), Aerobid® (flunisolide), Flovent® (fluticasone), and Azmacort® (triamcinolone). Qvar is a steroid using an environmentally friendly propellant (non-CFC). It delivers smaller-sized particles to the airways, which may improve the efficiency of delivery and allow lower doses.

Other long-term control drugs

Other drugs that may be prescribed for every day use to control asthma include:

• Long-acting beta-agonists -- These help control moderate-to-severe asthma, prevent nighttime symptoms, and prevent exercise-induced attacks. The drugs work by relaxing the muscles of your bronchial tubes and are effective for 12 or more hours after a single dose. They include Serevent® (salmeterol) and Foradil® (formoterol). IMPORTANT NOTE: These drugs are NOT formulated the same as "short-acting" beta-agonists, and should not be used for quick relief of symptoms. They are only for preventing symptoms from occurring in the first place. They are often used in combination with inhaled steroids -- they are generally not used as the only medicine to control asthma.

• Leukotriene modifiers -- These are relatively new drugs for patients with mild to moderate persistent asthma. Leukotriene modifiers are in the form of tablets. For mild asthma, they may be considered as an alternative to inhaled steroids. For moderate asthma, they may be considered as a supplement to inhaled steroids in place of long-acting beta agonists. They include Singulair® (monoleukast), which has been approved for children age two and older; Accolate® (zafirlukast), which has been approved for age five and older; and Zyflo® (zileuton), which is approved for patients age twelve and older.

• Theophylline -- This drug is used to help control mild to moderate persistent asthma, especially to prevent nighttime symptoms. However, it requires routine blood testing to make sure that the drug is within safe levels. The drug works by relaxing the muscles of your bronchial tubes; it is not an anti-inflammatory drug. Theophylline is used less now than it was in the past. Brands include Aerolate®, Choledyl®, Elixophyllin®, Quibron®, Slo-bid®, Theochron®, T-Phyl®, and Uniphyl®.

• Nedocromil and cromolyn -- These two drugs have similar anti-inflammatory effects and may be used to control mild persistent asthma. Cromolyn is available for use in a nebulizer, and therefore may be appropriate for young children. An example of nedocromil is Tilade®. An example of cromolyn is Intal®.

Combination therapy

For moderate to severe asthma, it is generally more effective to combine inhaled steroids with inhaled long-acting beta agonists than just use a steroid alone. This is because the steroid treats inflammation at the same time the beta agonist treats airway constriction (tightening). Combination therapy can lessen symptoms, help you breathe better, and reduce your reliance on relief medicine. The combination approach is recommended for many patients.

The two drugs can be taken with different inhalers, but a product that combines them into one inhaler (such as Advair Diskus®) may be more convenient and therefore likely to be used consistently. Advair Diskus is a dry powder inhaler approved for ages twelve and older.

For some patients, it may be appropriate to combine inhaled steroids with leukotriene modifiers or theophylline. However, the evidence for the effectiveness of these combinations is not as substantial.