Interaction of theophylline with erythromycin base in a patient with seizure activity.

A pediatric patient who was taking carefully monitored doses of theophylline for chronic asthma, was placed on erythromycin base for bronchitis. She subsequently developed theophylline toxicity which caused her to experience seizure activity. Any patient taking a theophylline preparation who is then placed on ANY of the available erythromycin compounds must have close monitoring of serum theophylline levels.