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Updated: Mar 20, 2026

Behavioral Characterization of Pentylenetetrazole-induced Seizures: Moving Beyond the Racine Scale
Published on: July 8, 2025
Safety, tolerability, and seizure control during long-term treatment with adjunctive brivaracetam for partial-onset
Manuel Toledo1, John Whitesides2, Jimmy Schiemann2
1Vall d'Hebron University Hospital, Independent University of Barcelona, Barcelona, Spain.
Objectives:
To report pooled safety/tolerability and seizure outcome data from adults with uncontrolled partial-onset (focal) seizures (POS) receiving adjunctive brivaracetam (BRV) during phase IIb/III and long-term follow-up (LTFU) studies.
Methods:
Seizure outcome data were pooled from phase IIb (NCT00175929 and NCT00175825), III/IIIb (NCT00490035, NCT00464269, NCT00504881, and NCT01261325) and associated LTFU studies (NCT00175916, NCT00150800, and NCT01339559). Safety/tolerability data were pooled from these studies plus NCT01405508, NCT01653262, and NCT01728077 (LTFU). Patients received placebo (during core studies) or BRV 5-200 mg/day. Safety/tolerability and seizure outcomes (BRV modal doses 50-200 mg/day) were assessed until January 17, 2014.
Results:
Of 2,186 patients (97.3% with POS and 2.7% with other seizure types) who received BRV 50-200 mg/day, 2,051 (93.8%) completed core studies and continued in LTFU studies. Total BRV exposure: 5,339.4 patient-years (≥8.0 years in 41 patients); 6-, 12-, 24-, and 60-month retention: 91.0%, 79.8%, 68.1%, and 54.4%, respectively. Safety/tolerability data pooled from 2,186 patients: ≥1 treatment-emergent adverse event (TEAE) reported by 1,848 (84.5%) patients; 1,184 (54.2%) reported ≥1 TEAE considered treatment-related. Most frequent TEAEs (≥10%): headache (20.9%), dizziness (17.5%), somnolence (15.2%), nasopharyngitis (13.2%), fatigue (11.3%), and convulsion (10.6%). Serious TEAEs (SAEs) and treatment-related SAEs: 401 (18.3%) and 95 (4.3%) patients, respectively. Of 28 (1.3%) deaths, four (14.3%) were considered possibly treatment related by the investigator. Pooled seizure outcome data (1,836 patients): median POS frequency/28 days at baseline was 8.9; on treatment, median percentage reduction from baseline in POS/28 days was 48.8%, and ≥50% responder rate was 48.7%. Complete seizure freedom: 4.9%, 4.2%, 3.0%, and 3.3% for ≥6, 12, 24, and 60 months, respectively. Improvements were seen in health-related quality of life (HRQoL) from baseline, assessed by Quality of Life in Epilepsy Inventory-31.
Significance:
Adjunctive BRV treatment in adults with POS was effective and generally well tolerated when administered long-term (≥8.0 years). Retention was high and HRQoL improvements were observed.
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Seizures: Classification
Seizures are typically classified into two main categories: focal and generalized seizures.
Focal Seizures
Focal seizures originate from specific regions of the brain. These seizures are further sub-classified into two types:

