What is a theophylline level?
A theophylline level is a measure of theophylline in the bloodstream. This is used to regulate the dose. A blood level between 5-15 µg/ml often gives good relief of symptoms with the fewest side effects. Some people may do better with a level less than 5 µg/ml. If the level is greater than 15, there is an increased risk of side effects.