Abstracts

Rationale: Several newer antiepileptic drugs (AEDs) have become available in the last fifteen years for treatment of seizures. In spite of this, a significant number of patients remain refractory to treatment with multiple AEDs. Phenytoin (PHT) has had extensive use as an efficacious antiepileptic medication in the past, but has fallen out of favor because of its side effect profile and propensity for drug interactions. The purpose of this study was to evaluate the role of PHT in the pediatric population in the current era of newer AEDs.Methods: Retrospective chart review of patients who were receiving PHT as monotherapy or add-on polytherapy was performed. These patients were identified from the clinic data base of children with epilepsy. Patients who were on PHT at first visit but were changed to an alternative AED by the treating physician because of concerns for side effects were excluded from the analysis. The following information was gathered: demographic data, underlying disorders, indication and dose, drug levels, concomitant AEDs, seizure control, and side effects. Results: Out of 2000 patients with epilepsy on AEDs, we identified 33 patients, 23M and 10F, aged between 3-24 years who were being treated with PHT. Underlying diagnoses included chronic static encephalopathy (7), cryptogenic epilepsy (7), mental retardation (4), tuberous sclerosis (3), metabolic/mitochondrial disorder (3), and other causes (9). Epilepsy was considered refractory in 15. Ten patients were on monotherapy with PHT. Three of these patients had previously failed another first line AED.Of the 23 patients on polytherapy, PHT was used as an add-on in 15. Concomittant AEDs were, levetiracetam (7), lamotrigine (6), sodium valproate (5), clonazepam (5), topiramate (3), and other AEDs (10). Seven patients were on 2 or more AEDs in addition to PHT. Four patients were on vagal nerve stimulator. Dose of PHT used ranged from 1.7 to10.6 mg/kg/day. Drug levels were available in 15 patients and ranged from 5.5 to 54.4 mcg/mL. Improved seizure control was observed in 19 (57.5%) patients. This included 4 patients who remained seizure free on PHT monotherapy, and 5 patients with refractory epilepsy. Twelve (36%) patients had poor control of seizures, 10 of whom had refractory epilepsy. PHT related side effects were noted in 15 (45%), with gum hyperplasia in 11, clinical symptoms of toxicity with supra-therapeutic drug levels in 5, elevated liver enzymes in one and bone fractures in 1.Conclusions: PHT remains a clinically relevant AED in the pediatric population for the treatment of seizures of diverse etiology in the era of newer AEDs. It may be worth a trial to use PHT in children with refractory epilepsy who have failed to respond to other AEDs.