Theophylline toxicity from an over-the-counter preparation.

The clinical presentation of theophylline poisoned patients has been well described in the literature. These individuals may develop severe and potentially fatal cardiac, neurologic, and gastrointestinal manifestations. While patients may present following an intentional over-dose, a significant percentage become toxic accidentally or iatrogenically, as a result of theophylline's narrow therapeutic index. Another factor, not well known or described in the literature, is the availability of theophylline in a variety of over-the-counter formulations. We present a case of theophylline toxicity from a nonprescription combination product containing theophylline, ephedrine, and phenobarbital. Clinicians should be aware of the potential for serious toxicity from over-the-counter medications, particularly those commonly thought of as "prescription only."