Omalizumab (Xolair) is a humanized anti-IgE monoclonal antibody that prevents binding of IgE to high-affinity receptors on basophils and mast cells. It is approved for moderate to severe allergic asthma in children 12 years of age and older. Xolair is delivered by subcutaneous injection every 2 to 4 weeks, depending on body weight and pretreatment serum IgE level.
Short-Acting β2-Agonists Short-acting β2-agonists, such as albuterol, levalbuterol, and pirbuterol, are effective bronchodilators that exert their effect by relaxing bronchial smooth muscle within 5 to 10 minutes of administration. They last for 4 to 6 hours. Generally a short-acting β2-agonist is prescribed for acute symptoms and as prophylaxis before allergen exposure and exercise. The inhaled route is preferred because adverse effects—tremor, prolonged tachycardia, and irritability—are less. Overuse of β2-agonists implies inadequate control; a change in medications may be warranted. The definition of overuse depends on the severity of the child’s asthma; use of more than one metered dose inhaler canister per month or more than eight puffs per day suggests poor control.
Ipratropium bromide is an anticholinergic bronchodilator that relieves bronchoconstriction, decreases mucus hyper-secretion, and counteracts cough-receptor irritability by binding acetylcholine at the muscarinic receptors found in bronchial smooth muscle. It seems to have an additive effect with β2-agonists when used for acute asthma exacerbations. Long-term use of anticholinergic medications in asthma is not supported by the literature.
Short bursts of oral corticosteroids (3 to 10 days) are administered to children with acute exacerbations. The initial startingdose is 1 to 2 mg/kg/day of prednisone followed by 1 mg/kg/dayover the next 2 to 5 days. Oral corticosteroids are available inliquid or tablet formulations. Prolonged use of oral corticosteroids can result in systemic adverse effects such as hypothalamic-pituitary-adrenal suppression, cushingoid features, weightgain, hypertension, diabetes, cataracts, glaucoma, osteoporosis, and growth suppression. Children with severe asthma mayrequire oral corticosteroids over extended periods. The doseshould be tapered as soon as possible to the minimum effectivedose, preferably administered on alternate days.
Approach to Therapy
Therapy is based on the concept that chronic inflammation is a fundamental feature of asthma and that the processes underlying asthma can vary in intensity over time, requiring treatment to be adjusted accordingly. Classification of asthma severity is emphasized for initiation of therapy in patients not currently receiving controller medications. Assessing control is emphasized for monitoring and adjusting therapy. A stepwise approach is used for management of infants and young children 0 to 4 years, children 5 to 11 years (Fig. 78-1), youths 12 years or older, and adults (Fig. 78-2). Medication type, amount, and scheduling are determined by the level of asthma severity or asthma control. Therapy is then increased (stepped up) as necessary and decreased (stepped down) when possible. A short-acting bronchodilator should be available for all children with asthma. A child with intermittent asthma has asthma symptoms less than two times per week. To determine whether a child is having more persistent asthma, using the Rules of Two is helpful: daytime symptoms occurring two or more times per week or nighttime awakening two or more times per month implies a need for daily anti-inflammatory medication.