Asthma medications are classified into two broad categories of quick relief and long-term control. Independent of severity, all persons with asthma should have a quick relief medication readily available. The class of medication most commonly used as quick relievers are short-acting β2-selective adrenergic agonists. (Table 43-3) Their mechanism of action is to stimulate β2-receptor on bronchial smooth muscle to cause relaxation. All are equally effective, have an onset of action within 5 minutes, a peak at 30 to 60 minutes and duration of 4 to 6 hours.8 The most common side effects associated with short-acting β2-agonists are tremor, anxiety, and tachycardia. Small dose dependent decreases in serum potassium and magnesium have been observed. Overuse of short-acting β2-agonists is defined as need for medication use for symptoms of asthma more than 2 days per week or more than twice in a month for nighttime awakenings.7 Long-term controller medication should be evaluated for patients who overuse short-acting β2-agonists. Of the long-term controller medications, "Inhaled corticosteroids constitute the drug class that has the greatest effect in helping patients achieve well-controlled asthma."5 Through their broad effects on gene transcription, they suppress but do not cure, multiple mediators of airway inflammation.9 All are equally effective at controlling bronchial inflammation and decreasing airway hyperresponsiveness, however, they are not equivalent on a microgram per microgram or puff per puff basis.7 In order to achieve maximum benefit they must be used on a daily basis and education must be provided that it will take at least 2 weeks to 1 month for full effect. The most common side effects of low to medium dose-inhaled corticosteroids are thrush and dysphonia.10 To minimize and prevent these side effects, persons with asthma should be encouraged to rinse and spit with water after inhaler use. At high doses over prolonged periods, patient's risk of developing adrenal suppression, osteoporosis, skin thinning, and cataract formation increases.1 To maintain a low to medium steroid dose, additional long-term medications such as long-acting β2-agonists, leukotriene modifiers, cromolyn, theophylline, and/or omalizumab (Xolair) are added based on patient's asthma severity. Current long-acting β2-agonists (LABA) have a duration of action of approximately 12 hours. Due to the SMART trial and subsequent black box warning in regard to increased risk of death, these medications should never be used alone for control of asthma.11 Subsequently, there are three formulations available: Fluticasone/salmeterol (Advair), budesonide/formoterol (Symbicort), and Mometasone/formoterol (Dulera). Leukotriene modifiers are divided into two categories to target inflammation. Two antagonize the leukotriene receptor where as the original drug, Zileuton, within this class acts as a 5-lipoxygenase inhibitor (Table 43-3). Common side effects are related to the gastrointestinal tract and most recently a caution has been added to monitor for behavior and mood changes. Zafirlukast absorption is affected by food and zileuton may elevate liver enzymes. Theophylline is currently considered as an adjunct option due to its long-acting bronchial dilatory properties, however, it is not used as often due to its narrow therapeutic range, dose-related side effects, and significant drug-drug interactions due to its metabolism via the CYP-450 enzyme system. An additional alternative is the use of the mast cell stabilizer cromolyn. It has an extensive safety profile with minimal side effects. However due to its short duration of activity requiring three to four times a day dosing and decreased efficacy compared to inhaled corticosteroids, it is considered an alternative for patients with mild persistent asthma. For patients who are not well-controlled despite high-dose inhaler corticosteroids, have a significant allergic component and meet weight criteria, omalizumab (Xolair) may be prescribed. Omalizumab is a monoclonal antibody that attaches to free circulating IgE to prevent it from binding to mast cells, thus inhibiting part of the inflammatory response. It is given as a subcutaneous injection every 2 to 4 weeks. The most common side effect is injection site reaction. The clinically significant side effect that prompted a black box warning was related to anaphylaxis that may occur at any time during treatment.