Understanding herb and dietary supplement use in patients with epilepsy.

Objective: To determine the prevalence of herb and dietary supplement use and to provide a comprehensive analysis of factors influencing the use of these products in patients with epilepsy.

Methods: We performed a cross-sectional study using self-administered questionnaires in a selected group of patients who were receiving care at a tertiary epilepsy center. Logistic regression was used to measure the association between the demographic variables and herb and dietary supplement use. In addition, we performed a MEDLINE search for each of the herb and dietary products used by our patients to determine the effect of these products on seizures and on their potential for interactions with other drugs metabolized by the liver.

Results: One hundred eighty-seven patients completed the survey. Fifty-six percent of this group of patients with epilepsy used herbs and dietary supplements at the time of the survey. A considerable portion (71%) of these patients reported the use of these products to their physician, and most of them relied on their physicians as the primary source of information. Most of the patients used dietary supplement for health promotion rather than to specifically benefit their epilepsy condition. Approximately one-third of patients used herb or dietary supplements that had the potential to increase seizures (16%) or to interact with hepatically metabolized drugs (19%). The most powerful independent predictors of herb and dietary supplement use were partial epilepsy [odds ratio (OR) 3.36; 95% confidence interval (CI) 1.27-8.88] and Caucasian race (OR 3.55; 95% CI 1.11-11.34).

Conclusion: Patients with epilepsy commonly used dietary supplements along with their antiepileptic medications. The majority of these patients used herb and dietary supplements for health promotion rather than because of dissatisfaction with conventional treatment. It is important that physicians involved in the care of patients with epilepsy routinely inquire about the use of dietary supplements and that they make use of reliable resources to assess the safety of these products with regard to modification of seizure risk and the potential for interactions with antiepileptic drugs.