Asthma Medicines

The use of epinephrine by injection for the treatment of asthma dates to as early as 1903. An aerosol form was developed around 1910. For many decades epinephrine was the only available medication for the treatment of bronchial asthma. Its use in the emergency setting has certainly saved countless numbers of lives.

In view of the fact that epinephrine is a nonselective agent that has potent effects on the heart and circulation, its use for treating bronchial asthma has declined. In elderly patients in particular, administration of epinephrine may result in increases in blood pressure and heart rate. These effects may contribute to the development of stroke and heart attack. For these reasons, emergency room treatment of bronchial asthma usually consists of the administration of a selective B-adrenergic agonist by nebulization.

For Anaphylaxis

Epinephrine is still an important medication for treating severe allergic reactions. It is the treatment of choice for a severe reaction known as anaphylaxis, a total body allergic reaction that may lead to collapse or shock. One example is the severe reaction to a bee sting in a sensitive individual. Injectable preparations of epinephrine that automatically inject a premeasured dose are available by prescription for highly allergic patients.

Over-the-Counter Medication

Over-the-counter nonprescription preparations of aerosol epinephrine should be avoided. These preparations are extremely weak and short acting with effects that may last only a few minutes, and therefore are commonly abused. With the far more effective treatment available for bronchial asthma I feel these agents would best be withdrawn since they may actually deter patients from seeking appropriate and necessary medical attention.

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An asthmatic attack is one of the most striking medical emergencies. One of my first experiences with severe asthma was in the intensive care unit of Bellevue Hospital. I had been called to consult on a fifty-six-year-old woman who was having a severe asthmatic attack. As I entered the unit and approached the bedside, I noted several physicians already in attendance. The patient was sitting upright with labored breathing and I could hear her wheezing from several feet away. It was clear that she was not doing well despite continuous oxygen and medicated aerosol treatment. Unable to speak due to shortness of breath, her expression was one of fear and desperation. Several days later, greatly improved after vigorous treatment, I asked her to describe what she had been feeling during her attack. “It was like I was drowning.”

In the asthmatic attack there is constriction or tightening of the bronchial wall muscle, and secretion of mucus, often with “plugging” of small air tubes, as well as inflammation and swelling of the bronchial lining. The end result is blockage or obstruction of the bronchial tubes. The frequency, duration, and severity of the asthmatic attack varies markedly from patient to patient.

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Cromolyn sodium, a derivative of khellin, an Egyptian herbal remedy, is a useful anti-inflammatory agent that may be used as an alternative to inhaled corticosteroids. In severe patients, cromolyn sodium (Intal) may be used in conjunction with steroids. Like the inhaled corticosteroids, cromolyn is also underused. This underutilization does not result from fear of adverse effects but rather from a misunderstanding of its application. Since its introduction, cromolyn has been the drug of choice for childhood asthmatics. From this early application it has been incorrectly assumed that it was a poor drug for adults, particularly those without allergic characteristics. Many studies, however, have documented that cromolyn may be an effective drug for asthmatics of all ages, even in patients with “intrinsic” asthma. It is also clear that cromolyn does not work for all patients. Like the inhaled corticosteroids, it is slow acting and therefore requires a trial of three to six weeks to assess response. Because of this, many patients abandon this drug before it has had an adequate trial.

How Does Cromolyn Work?

It is not clear how cromolyn sodium reduces inflammation. Some evidence has pointed to an action on inflammatory and allergy cells that prevents release of irritating chemicals that cause inflammation. There may also be an antagonistic action on nervous stimulation that prevents bronchoconstriction and reflex cough. Cromolyn has been demonstrated to prevent both the immediate and late reactions of asthma as well as exercise induced asthma in many patients.

How Cromolyn Is Supplied and Used

Cromolyn sodium was initially made available as a powder for inhalation. Unfortunately, this produced considerable coughing and wheezing. It is currently also available as an aerosol for metered-dose inhalers and in solution for nebulization. When used for nebulization it may be combined with a B2-adrenergic agonist. The recommended dosage is two puffs four times a day from an MDI or 20 mg in solution via a nebulizer, also four times a day.

Cromolyn is not an effective drug for acute asthmatic attacks and, like the inhaled corticosteroids, must be used as a preventive maintenance drug. For this reason cromolyn is best not started during an acute attack. It can be introduced toward the end of an oral steroid taper similar to the way that the inhaled corticosteroids are started. Also, like the inhaled corticosteroids, cromolyn can be used alone and does not necessarily require premedication with a B-adrenergic agonist.

Adverse Effects of Cromolyn

Besides being an effective drug, cromolyn has an extremely low incidence of side effects, which explains its first-line use in children where high-dose inhaled corticosteroids have been shown to slow bone development. In adults the inhaled corticosteroids are considered more effective, making cromolyn a second line agent. In those patients with adverse steroid effects cromolyn is an excellent alternative anti­inflammatory. There are few adverse effects to speak of. Occasionally, cough and wheezing may result from its inhalation. This can often be prevented with the use of a B-adrenergic agonist sprayed five to ten minutes before use or given in solution with cromolyn via nebulization. Rarely have total body effects been noted. An extremely small number of patients have noted joint pains and rash. These effects have resolved completely on discontinuation.

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