Vagus nerve stimulation (VNS) was shown to reduce seizure frequency in refractory epilepsy patients in two pilot studies. Based on these results, a multicenter, prospectively randomized, parallel, double-blind study of patients with refractory partial seizures was initiated. After a 12-week baseline period, identical vagus nerve stimulators were implanted and patients randomized to either a high or low 14-week VNS treatment paradigm. The primary objective was to demonstrate that high VNS (therapeutic parameters) was more effective in reducing partial seizure frequency than was low VNS (less or noneffective parameters). Patients continued receiving antiepileptic drugs (AEDs) with plasma concentrations held constant throughout the study. We report results of the first 67 patients to exit the 14-week acute phase. After 14 weeks of VNS, 31 patients receiving high VNS experienced a mean seizure frequency percentage reduction of 30.9%, which was statistically significant as compared with the mean seizure frequency percentage reduction of 11.3% in 36 patients receiving low VNS (p = 0.029, t test; p = 0.036, Wilcoxon rank-sum test). In addition to the significant intragroup p-values, mean seizure frequency percentage change reached statistical significance for high VNS (p < 0.001) but not low VNS (p = 0.072) as compared with baseline. Twelve of 31 (38.7%) patients receiving high VNS achieved at least 50% reduction in seizure frequency whereas 7 of 36 (19.4%) patients receiving low VNS experienced at least 50% reduction after 14 weeks. The implant procedure and VNS therapy were well tolerated. Our study confirmed the effectiveness of VNS as treatment for epilepsy patients with refractory partial seizures.

Valproate monotherapy was associated with significantly greater weight gain than lamotrigine monotherapy. Weight gain associated with valproate was significant within 10 weeks after initiating therapy and continued throughout the study. Efficacy of lamotrigine was comparable with that of valproate; lamotrigine tended to be better tolerated.

To assess the clinical characteristics of valproate (VPA)-associated pancreatitis, information from three sources was gathered: (a) a survey among 507 physicians with a special interest in treatment of epilepsy, (b) a review of the authors' patient population, and (c) a review of the literature. Of 366 physicians answering the survey, 53 (14.5%) reported a case of pancreatitis. Thirty-nine cases were available for review (24 from the medical literature, 12 from the survey, and 3 from the authors). Pancreatitis appeared to be more frequent in young persons (mean age 16.4 years) but may occur at any age. The highest risk appears to exist during the first months of treatment: 43.8% of the cases developed during the first 3 months, and 68.8% developed during the first year. Seventy-six percent of patients were receiving polytherapy, and 41% had some form of associated chronic encephalopathy. In most patients, the reaction was rapidly reversible when VPA was discontinued. It was severe in 6 patients, with 3 deaths reported. Rechallenge with VPA was attempted in 9 patients, with a high incidence of relapses. Asymptomatic elevation of serum amylase in patients receiving VPA was reported by 40 (10.9%) of the physicians surveyed. Awareness of the problem and early discontinuation of VPA may be effective in preventing serious reactions.

SummaryAlthough the treatment of patients with epilepsy who are mentally retarded and have multiple handicaps has generally involved polypharmacy, there is an emerging trend towards simplified antiepileptic drug (AED) regimens. A prospective study of reduction in the number of AEDs was conducted in an institutionalised population of profoundly retarded patients with epilepsy and multiple handicaps. Of 44 patients with uncontrolled generalised seizures who were receiving 4 or 5 AEDs in our study, 28 (64%) achieved monotherapy and the remaining 16 (36%) achieved duotherapy, with significantly improved seizure control and reduced intensity of seizures (although seizure frequency increased transiently in some patients following withdrawal of primidone and phenobarbital). 14 patients (32%) became seizure-free: 13 received monotherapy and I received duotherapy. The remaining patients had ~ 50% reduction in seizure frequency while receiving monotherapy (15 of 28) or duotherapy (15 of 16). The majority of patients who became seizure-free were receiving divalproex sodium or a combination of divalproex and phenytoin. After dosage reduction to regimens with I or 2 drugs, most patients showed more positive behaviours and became more sociable. Overall treatment costs were also markedly reduced. We conclude that AED reduction to mono-or duotherapy is desirable in patients with multiple handicaps and refractory seizures who are receiving polypharmacy regimens.