Two medications should be used only if the two provide an advantage over one. More than two maintenance medications for asthma are occasionally justified for patients with severe asthma. Intervention measures must still be available for breakthrough symptoms. No maintenance medications reliably prevent all acute exacerbations, especially those triggered by viral respiratory infections. For patients requiring long-term maintenance medications, careful consideration should be given to treatment measures that do not involve medication.
Some patients have their asthmatic symptoms reduced with environmental measures.
While some environmental exposures such as cigarette smoke and wood burning stoves are common irritants that can worsen asthma in many patients, others involve allergic reactions to substances that are otherwise harmless to nonallergic people. Identification of allergy as a cause of asthma requires evaluation by a physician knowledgeable about environmental allergens who will review the medical history of symptoms and perform tests to identify allergic antibody to environmental allergens. In some cases, the use of allergy shots may be considered as an effort to decrease sensitivity to inhalant allergens judged important in triggering asthma. Inhaled corticosteroids that have a high degree of topical potency at low delivered doses have been available in the U.S. since 1977 with experience elsewhere for several years prior to that. They are the most effective single medications for asthma.