ObjectivesIntracerebral hemorrhage (ICH) has the highest morbidity and mortality rate of any stroke subtype and clinicians often administer prophylactic antiseizure medications (ASMs) as a means of preventing post-stroke seizures, particularly following lobar ICH. However, evidence for ASM efficacy in preventing seizures and reducing disability is lacking given limited randomized trials. Herein, we report analysis from a large prospective observational study that evaluates the effect of primary prophylactic ASM administration on seizure occurrence and disability following ICH. Materials and methodsPrimary analysis was performed on 1630 patients with ICH enrolled in the ERICH study. A propensity score for administration of prophylactic ASM was developed and patients were matched by the closest propensity score (difference < 0.1). McNemar's test was used to compare occurrence of in-hospital seizure and disability, defined by modified Rankin Score (mRS) ≥ 3 at 3 months post ICH. ResultsOf the 815 matched pairs of patients treated with primary prophylactic ASM, there was no significant difference in seizure occurrence (p = 0.4631) or disability (p = 0.4653). Subset analysis of 280 matched pairs of patients with primary lobar ICH similarly revealed no significant difference in seizure occurrence (p = 0.1011) or disability (p = 1.00) between prophylactically treated and untreated patients. ConclusionsAlthough current guidelines do not recommend primary prophylactic ASM following ICH, clinical use remains widespread. Data from the ERICH study did not find an association between administering primary prophylactic ASM and preventing seizures or reducing disability following ICH, thus providing evidence to influence clinical practice and patient care.