Abstracts

RATIONALE: Excessive daytime somnolence (EDS) in epilepsy patients may result from a variety of causes, especially antiepileptic drug toxicity. The use of stimulant medications to treat EDS in epilepsy patients may cause concern about safety, particularly the possible exacerbation of seizures. Modafinil has recently become available in the United States for treatment of EDS in narcolepsy, and we undertook an open-label pilot study of its safety, tolerability, and efficacy for EDS in intractable epilepsy patients.
METHODS: Patients with epilepsy were screened for EDS without historical evidence of obstructive sleep apnea. Modafinil was given in an open-label add-on design, beginning at 100 mg every morning. If needed, the dosage could be increased to 200 mg. Patients were assessed using a 10-point Likert scale for tolerability and efficacy in reducing EDS. Safety was assessed by query for side effects and changes in seizure frequency. Anticonvulsants were not decreased during the evaluation period.
RESULTS: Six patients were treated (4 females). Mean age was 28.2 [plusminus] 6.5 (standard deviation) years. All patients had intractable partial epilepsy, with a baseline seizure frequency of 2.2 [plusminus] 3.0 seizures/month, and were taking 1-4 antiepileptic drugs (mean: 2.3). Two patients had failed temporal lobectomy, one of whom also had a vagal nerve stimulator. Five patients were treated with 100 mg/day, and one with 200 mg/day. After treatment with modafinil for an average of 41 days, the mean seizure frequency was 1.3 [plusminus] 1.4 seizures/month (change from baseline frequency: p[gt]0.3). Tolerability was rated as 8.2 [plusminus] 3.6 on the Likert scale, and efficacy in treating EDS was rated at 6.3 [plusminus] 4.4. A single patient felt that modafinil increased seizure frequency, although this was not corroborated by seizure calendar data. This patient used modafinil only four days. Transient side effects were reported by two patients, and included [dsquote]too much energy[dsquote] and [dsquote]irritability.[dsquote] These resolved with continued use.
CONCLUSIONS: Modafinil is safe as treatment for EDS in patients with intractable epilepsy. Seizure frequency does not increase with its use. Doses considerably below those used in narcolepsy significantly improve EDS, and modafinil is well-tolerated. Whether the effects are due entirely to treatment of antiepileptic drug side effects, or are due to other effects of the compound, remains to be determined in a larger study. More prolonged investigation in a larger epilepsy population is warranted. The safety of modafinil in this patient population suggests that wider use in epilepsy patients is reasonable.
Support: MidAmerica Neuroscience Institute.