Predisposing factors to apparent theophylline-induced seizures

Area of Science:

• Neurology
• Clinical Pharmacology

Background:

• Theophylline is a bronchodilator with a narrow therapeutic index.
• Theophylline toxicity can manifest as seizures, particularly at elevated serum theophylline concentrations (STC).
• Understanding risk factors and clinical presentation of theophylline-induced seizures is crucial for patient safety.

Purpose of the Study:

• To characterize the clinical features and risk factors of theophylline-related seizures in a patient cohort.
• To compare the characteristics of patients experiencing seizures with a control group.

Main Methods:

• Retrospective review of 15 patients who experienced theophylline-related seizures over 3 years.
• Analysis of patient demographics, theophylline dosage, STC, co-administered medications, and pre-existing conditions.
• Comparison with a control group of asymptomatic theophylline users.

Main Results:

• 13/15 patients were on oral theophylline; 11/15 had factors impairing metabolism (URI, liver dysfunction, cimetidine).
• Patients on oral therapy received higher doses (>17 mg/kg/day) compared to controls (P < .01).
• 73% had abnormal neurologic history or imaging, but no acute mortality or morbidity was observed.

Conclusions:

• Theophylline-related seizures in this cohort were associated with impaired metabolism, higher oral doses, and pre-existing neurological conditions.
• Clinical presentation differed from prior reports, with lower STC and better outcomes.
• Close monitoring of patients on theophylline, especially those with risk factors, is essential.