Asthma is a disorder that produces episodic attacks separated by times with few or no symptoms. Attacks usually start abruptly with shortness of breath and wheezing. Triggers can be environmental irritants or allergens, diet, exercise, stress and emotion. Cromolyn sodium does not relieve individual attacks but alters the biochemistry underlying your body's reactions to environmental, allergic and exercise triggers.
Asthma Biochemistry
For some people with asthma, allergens or exercise can trigger reactive cells in their airways (mast cells) to release chemicals, most notably a slow-reacting-substance of anaphylaxis (SRS-A), which set off a cascade of protective mechanisms. But if too many mast cells react or if your lungs are too sensitive to the chemicals, the muscles in your airways begin to constrict (bronchospasm). Airway tightening increases your work of breathing, makes you short of breath and causes wheezing--an asthma attack.
Long-Term Prevention
One strategy to prevent asthma attacks is to stabilize your mast cells. In 1965, Dr. Roger Altounyan, a British medical researcher, discovered a chemical, cromolyn sodium, able to do just that. It was easily administered by inhalation in water-based mist or as powder. The drug produced almost no side effects. Cromolyn sodium did not abort attacks in progress, but after a few days of therapy, asthma attacks became milder and less frequent.
Administration
Cromolyn sodium (brand name Intal) was marketed in a metered-dose inhaler. However, the hydrofluorocarbon propellant stopped production due to industry-wide recognition of environmental effects. Altounyan, discoverer of cromolyn sodium, also invented the "Spinhaler," a device for inhaling 20mg of the medication as a dry powder. Cromolyn sodium, 20mg in water, can also be delivered by an air or oxygen powered nebulizer, typically four times a day.
Side Effects
Inhalation of cromolyn sodium powder is irritating to airways and can cause bronchospasm. The sodium in the compound causes airway reactions. This is overcome by adding a small amount (0.1 mg) of isoproterenol, a short-acting bronchodilator.
Rare throat irritation usually responds to sipping water before and after dosing, and mild, transient nasal congestion has been reported. Some of the dose is inevitably swallowed, so side effects attributed to cromolyn sodium oral administration (for conditions other than asthma) in less than 5 percent of patients, also occur in asthmatic users. They include diarrhea and headache. Generally, cromolyn sodium is considered safe and free of side effects.
Future Asthma Benefits
Dr. Alan Edwards, a British researcher at the David Hyde Allergy and Research Centre, says that asthma patients using cromolyn sodium have occasionally noticed effects on other conditions. This has led to further research on the biochemistry behind cromolyn sodium and revealed new gastrointestinal, dermatologic, ophthalmic and other uses. Edwards believes the broadening science stimulated by the original asthma-use--more than 20 new cromolyn-like compounds have been synthesized and studied--may eventually come full-circle, bringing even more advances to the treatment of asthma.
