What is Asthma?
These medications quickly control acute asthma attacks.
Beta2-agonists do not reduce inflammation or airway responsiveness but serve as bronchodilators, relaxing and opening constricted airways during an acute asthma attack. They are used alone only for patients with mild and intermittent asthma. Patients with more severe cases should use them in combination with other drugs.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, and Medihaler-Iso), metaproterenol (Alupent, Metaprel), pirbuterol (Maxair), terbutaline (Brethine, Brethaire, and Bricanyl), and bitolterol (Tornalate).
- Newer beta2-agonists, including levalbuterol (Xopenex), have more specific actions than the standard drugs. Studies have indicated that levalbuterol is as effective as albuterol with fewer side effects.
Short-acting bronchodilators are generally administered through inhalation and are effective for 3 - 6 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, patients should discuss corticosteroids or other drugs to treat underlying inflammation.
Side Effects of Beta2-Agonists. Side effects of all beta2-agonists include:
- Fast and irregular heartbeats. Notify a doctor immediately if this side effect occurs, particularly in people with existing heart conditions. Such patients face an increased risk for sudden death from cardiac related causes.
Beta2-agonists have serious interactions with certain other drugs, such as beta-blockers, and patients should tell the doctor about any other medications they are taking. People with diabetes, heart disease, high blood pressure, hyperthyroidism, an enlarged prostate, or a history of seizures should use these drugs with caution.
Loss of Effectiveness and Overdose. Short-acting beta2-agonists become less effective when taken regularly over time, which increases the risk for overuse. Overdose can be serious and in rare cases even life threatening, particularly in patients with heart disease.
Two inhaled drugs, ipratropium bromide (Atrovent) and tiotropium (Spiriva) act as bronchodilators over time. Neither is highly beneficial for acute asthma attacks. Moreover, the drugs are not approved specifically for asthma. They may, however, have some benefits:
- They may be useful for certain older patients with asthma who also have emphysema or chronic bronchitis.
- Combining them with a beta2-agonist might help patients who do not initially respond to treatment with a beta2-agonist alone.
Oral (Systemic) Corticosteroids
Common oral corticosteroids include prednisone, prednisolone, methylprednisolone, and hydrocortisone. They very effectively reduce inflammation. They are generally used for asthma flareups that do not respond to inhaler medications. In some severe cases, they may be used as maintenance therapy. Usually, the dosage starts out higher and is then gradually reduced over a 5 - 7 day period.
Adverse effects of prolonged use of oral steroids include cataracts, glaucoma, osteoporosis, diabetes, fluid retention, susceptibility to infections, weight gain, hypertension, capillary fragility, acne, excess hair growth, wasting of the muscles, menstrual irregularities, irritability, insomnia, and psychosis. Osteoporosis (bone thinning) is a common and particularly severe long-term side effect of prolonged steroid use.Osteoporosis is a condition characterized by progressive loss of bone density, thinning of bone tissue, and increased vulnerability to fractures. Osteoporosis may result from disease, dietary or hormonal deficiency or advanced age. Regular exercise and vitamin and mineral supplements can reduce and even reverse loss of bone density.
No one should stop taking any steroids without consulting a doctor first. If the doctor orders steroids withdrawn, regular follow-up monitoring is necessary. Patients should talk to their doctor about ways to prevent adrenal insufficiency during withdrawal, particularly during stressful times when the risk increases.