Quick-Relief Medications

These medications quickly control acute asthma attacks.

Short-Acting Beta2-Agonists

Beta2-agonists do not reduce inflammation or airway responsiveness but serve as bronchodilators, relaxing and opening constricted airways during an acute asthma attack. A short-acting inhaled beta2-agonist, taken as needed, is often the only medication used by children with chronic mild asthma.

Asthma is a disease in which inflammation of the airways causes airflow into and out of the lungs to be restricted. When an asthma attack occurs, mucus production is increased, muscles of the bronchial tree become tight, and the lining of the air passages swells, reducing airflow and producing the characteristic wheezing sound.

Specific short-acting beta2-agonists include:

• Albuterol (Proventil, Ventolin), called salbutamol outside the U.S., is the standard short-acting beta2-agonist in America. Other similar beta2-agonists are isoproterenol (Isuprel, Norisodrine, Medihaler-Iso), metaproterenol (Alupent, Metaprel), pirbuterol (Maxair), terbutaline (Brethine, Brethaire, Bricanyl), and bitolterol (Tornalate). Isoetharine (Bronkometer, Bronkosol) is available in nebulizers.
• Newer beta2-agonists, including levalbuterol (Xopenex), have more specific actions than the standard drugs. Xopenex is administered with a nebulizer, and studies have indicated that it is as effective as albuterol with fewer side effects. The original formulation of Xopenex was administered with a nebulizer. A new metered-dose inhaler formulation was launched at the end of 2005. It is approved for children age 4 years and older.

Short-acting bronchodilators are generally administered through inhalation and are effective for three to six hours. They relieve the symptoms of acute attacks, but they do not control the underlying inflammation. If asthma continues to worsen with the use of these drugs, a doctor may prescribe corticosteroids or other drugs to treat underlying inflammation.

Side Effects of Beta2-Agonists. Side effects of all beta2-agonists include:

• Anxiety
• Tremor
• Restlessness
• Headache
• Fast and irregular heartbeats. A doctor should be notified immediately if this side effect occurs.
• These drugs should be taken with caution by children with diabetes or a history of seizures.
• Beta2-agonists have serious interactions with certain drugs and parents should tell the doctor about any other medications their child is taking.

Loss of Effectiveness and Overdose. There has been some concern that short-acting beta2-agonists become less effective when taken regularly over time, increasing the risk for overuse. Over time some patients may become tolerant to many effects of short-acting beta2-agonists. The degree to which this affects the airways is uncertain. In some studies, the duration of action has declined but the peak effect appears to be preserved, making these drugs still useful for acute attacks. Regular use of long-acting beta2-agonists may increase the chances of a reduced effect from the short-acting forms.

A 2005 landmark study suggested that patients’ differing clinical response to albuterol may be based on their genotype. Albuterol targets the beta-adrenergic receptor. In the Beta-Adrenergic Response by Genotype (BARGE) trial, researchers studied the effects of albuterol on patients with two different forms of this receptor. The results suggested that patients with the arginine form of the receptor did not respond to albuterol. These patients’ asthma symptoms actually improved when albuterol was not used. By contrast, patients with the glycine form of the receptor had improved asthma control with albuterol.

Anticholinergic Drugs

Inhaled ipratropium bromide (Atrovent) acts as a bronchodilator over time. Ipratropium bromide alone is only modestly beneficial for acute asthma attacks. In fact, the drug is not approved specifically for asthma. Some parents report benefit for treating wheezing in infants. It is also sometimes used in the emergency room to treat children with severe asthma to enhance the effects of intravenous beta2-agonists.

Oral Corticosteroids

Common systemic oral corticosteroids include prednisone/prednisolone, dexamethasone, methylprednisolone, and hydrocortisone. They reduce inflammation very effectively, but children generally take them for only 5 days after hospitalization for an acute attack. Compliance among children can be low, however, since these drugs have a bitter taste and can cause vomiting. Taking oral dexamethasone for 2 days may be as effective and more tolerable than the standard 5-day regimen of prednisone/prednisolone. Prolonged use of oral steroids has widespread and sometimes serious side effects, so they are not generally give to children for longer than a few days.

[For more information on medications, see In-Depth Report #04: Asthma in adults.]

---

Review Date: 3/18/2006
Reviewed By: Harvey Simon, MD, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital.