Status epilepticus (SE) and seizure clusters (SC) represent neurologic emergencies with a case fatality rate up to 34%, depending on cause and comorbidity. As SE becomes more refractory to treatment over time, appropriate medication is important. This study aimed to investigate efficacy and tolerability of intravenous (IV) lacosamide (LCM) in treatment of SC and SE. Data of patients with SE or SC who were treated with IV LCM between December 2009 and February 2011 in two Austrian centers were analyzed retrospectively. Clinical information was extracted from patients’ charts. Forty-eight patients (26f/22m) aged median 62 years (range 17–95 years) were identified. Thirty-five percent of patients (17 of 48) had SC and 65% (31 of 48) had SE. SE was nonconvulsive in 10 (32%), convulsive in 11 (36%), and focal in 10 (32%) patients. SE was acute symptomatic in six (20%) and remote symptomatic in 11 (35%) patients. Fourteen (45%) had preexisting epilepsy. Median initial bolus dose was 200 mg (range 200–400 mg) in patients with SE and 200 mg in patients with SC. Maximum infusion rate was 60 mg/min. Cessation was observed in 42 patients (88%). Success rate in patients with SE receiving LCM as first or second drug was 100% (8 of 8), as third drug 81% (11 of 15), and as fourth or later drug 75% (6 of 8). There were no side effects observed except for pruritus and skin rash in two patients. These data support use of IV LCM as a potential alternative to standard antiepileptic drugs for acute treatment of seizure emergency situations, although randomized controlled studies are needed.