What is considered theophylline toxicity in lab values?

Theophylline toxicity is commonly associated with serum theophylline levels that exceed the therapeutic range, which is typically between 10 to 20 mcg/ml. A level of 25 mcg/ml indicates that theophylline is reaching a point where adverse effects might begin to manifest, leading to toxicity. Toxicity can produce symptoms such as nausea, vomiting, and potentially serious cardiac and central nervous system effects.

In this context, a level of 25 mcg/ml falls above the upper limit of the therapeutic range and indicates potential toxicity. Levels at or below 15 mcg/ml and 10 mcg/ml are considered within the normal range for therapeutic effect, which is why they would not be categorized as toxic. A level of 30 mcg/ml clearly exceeds levels that are commonly recognized as toxic, but typically, a lower level like 25 mcg/ml often serves as a threshold where toxicity may start to be observed in patients.