Preliminary study of zonisamide monotherapy in de novo patients with early Parkinson's disease

Abstract

AbstractBackgroundLittle is known about single administration of zonisamide in Parkinson's disease patients.AimWe aimed to evaluate the therapeutic effects of zonisamide monotherapy in early Parkinson's disease patients.MethodsA total of 10 untreated (de novo) patients with Yahr stage I or II participated. Zonisamide was given at a daily dose of 25 mg for 1 month and increased to 50 mg for the next 2 months. Unified Parkinson's Disease Rating Scale parts I–IV and tremor‐related Unified Parkinson's Disease Rating Scale (items 16, 20 and 21) were examined every month. Serum zonisamide concentrations and urinary homovanillic acid concentrations were measured. Three patients had rapid eye movement sleep behavior disorder. Sleep condition was asked to patients? spouses.ResultsAt 1 month after zonisamide treatment, Unified Parkinson's Disease Rating Scale scores did not differ from the baseline scores statistically. At 2 and 3 months after zonisamide treatment, Unified Parkinson's Disease Rating Scale part III and tremor‐related scores were reduced significantly compared with pretreatment (P < 0.01). Sleep state improved markedly in three patients with rapid eye movement sleep behavior disorder at 1–2 months after zonisamide treatment. The mean serum concentrations of zonisamide (standard deviation) were 2.0 μg/mL (0.9) at 25 mg/day and 6.6 μg/mL (2.3) at 50 mg/day. Urinary homovanillic acid concentrations were not altered before and after zonisamide administration.ConclusionsThe present study showed that zonisamide monotherapy improved motor and sleep dysfunction in de novo patients with early Parkinson's disease. Significant therapeutic benefits were present within 1–2 months. Finally, the data highlight a therapeutic potential of zonisamide monotherapy in tremor‐predominant patients with early Parkinson's disease.