Serum theophylline during acute asthmatic attacks.

To investigate serum theophylline levels during acute attacks of asthma, venous blood samples were taken from 41 consecutive patients. 36 had asthma and 5 suffered from chronic bronchitis. The patients were taking five different theophylline preparations. Blood samples were taken when the patients were admitted to the emergency unit because of serious deterioration in their pulmonary condition. Serum theophylline was analyzed by liquid column chromatography. 26 patients revealed subtherapeutic levels, 5 patients had levels above therapeutic range, and 10 patients had values within the therapeutic range. Thus, many patients taking oral theophylline derivatives are undertreated and a few are overmedicated.