Pharmacologic Approaches to Obstructive Airway Disease

Abstract

We have outlined the various bronchodilator medications currently employed in chronic obstructive airways disease. A knowledge of the pharmacology of the lung and the sites of action of these medications should make it possible to combine them in ways that will promote the most benefit for the patient with the least side effects. A logical format for approaching the patient with chronic obstructive airways disease is listed below. Frequently, for the patient with mild or intermittent symptoms of airways obstruction, an inhaled beta agonist will suffice. This may be taken regularly and as needed (for example, prior to vigorous exercise). For patients with more symptoms or those who cannot be controlled on a single agent, a long-acting theophylline preparation should be initiated. Usually, a 12-hour sustained release tablet is preferable. Bedtime dosing may prevent nocturnal shortness of breath. The factors affecting theophylline metabolism should be kept in mind, and theophylline levels should be obtained in those situations where there is an inadequate or inappropriate clinical response. The combination of an oral theophylline and an inhaled beta agonist should suffice in approximately 80 per cent of patients with chronic obstructive airways disease. For those patients who still have symptoms and in whom no other precipitating factor, such as infection or allergy, has been defined, additional therapy can be initiated. For outpatients, this usually consists of the addition of an oral beta agonist, starting at the lowest dose first. If tachyphylaxis appears to be developing, then aerosol atropine or initiation of corticosteroids should be considered. The addition of mucolytics, mist, and chest physiotherapy will frequently reduce the need for additional measures.