Abstract

Objective: Dravet syndrome is a developmental and epileptic encephalopathy
characterized by severe and drug-resistant seizures in early childhood, followed by
developmental delay. The purpose of this study was to investigate aspects of pharmacological treatment of Norwegian patients with Dravet syndrome, focusing on the
use of antiseizure medicines (ASMs) and identifying treatment challenges.
Methods: Patients were identified through medical registries at the National Center
for Epilepsy in Norway and National Center for Rare Epilepsy Related Disorders
during 2008-2018. Additional clinical data were obtained from medical records and
laboratory request forms.

Results: We identified 53 patients with Dravet syndrome, 30/23 males/females, aged
2-50 years. The majority of patients with known seizure frequency experienced frequent seizures, 80% (n = 35/44). Only two patients were seizure-free. Valproate
(n = 48), clobazam (n = 45), levetiracetam (n = 30), and stiripentol (n = 38) were
most commonly used, previous or current use. More than one-third (n = 20) had
tried sodium channel blockers (including lamotrigine), but these drugs were used less
during the last decade. Polytherapy was common, 81% (n = 43) used two or more
ASMs, and eight of these patients used 4-5 drugs (15%). Several challenges were
identified: high seizure frequency, comorbidities, treatment changes with a wide
range of ASMs, common use of oral gastro-tubes, extensive polypharmacy, and drug
interactions.

Significance: The use of ASMs has changed over the last decade, in accordance with
updated international recommendations. Various treatment challenges were identified. This vulnerable group of patients needs close follow-up for an optimal treatment outcome.

KEYWORDS
antiseizure medicines, Dravet syndrome, epilepsy, polypharmacy