Experience with theophylline for the management of chronic asthma

Even with the availability of new and exciting antiasthmatic drugs, theophylline is emerging as one of the most useful noncorticosterioid agents available for suppressing symptoms in the patient with chronic asthma. Maximal benefit, however, requires appreciation of recent developments related to the pharmacodynamics and pharmacokinetics of theophylline. Serum theophylline concentrations between 10 and 20 microgram/ml are most likely to result in benefit without toxicity. A wide range of doses is required to attain these serum concentrations as a function of individual variability in the rate of drug elimination. Sustained-release theophylline preparations, when reliably and completely absorbed, offer major therapeutic advantage by minimizing fluctuations in serum concentrations and consequent variation in effect between doses. Moreover, this stabilization of the airway hyperreactivity of asthma can be attained with 12-hour dosing for most patients with one of the newer formulations. Initiation of therapy with low doses and determination of final dosage by measurement of serum theophylline concentration is essential for safe and effective use of this drug. Based upon cumulative frequency distributions, a simple and efficient dosing schedule had been developed that virtually eliminates problems of intolerance to the drug. About 99% of children and almost as many adults tolerate theophylline without adverse effects when used in this manner and most patients can be maintained virtually free of asthmatic symptoms with theophylline as the only chronic medication.