Use of a twelve-hour theophylline preparation in chronic adult asthmatics.

Twenty-one adult chronic asthmatic patients were studied while taking a 12-hour sustained-action theophylline tablet. Pulmonary function testing and serum theophylline levels were monitored for 12 weeks, including testing every two hours over one dosing interval on the final day of the study. Results indicate the preparation tested produced sustained stable theophylline levels for a full 12 hours, with pulmonary function also remaining elevated and stable during this period. There was minimal toxicity reported over the 12-week period and no evidence of tolerance.