Clinical characteristics of acute lacosamide poisoning: Pavia Poison Control Centre experience

Lacosamide is a third-generation antiepileptic drug used as adjunctive therapy for partial seizures. Since its approval in 2008 very few cases of lacosamide overdose have been described in literature. The aim of our study was to evaluate clinical characteristics of acute lacosamide poisoning.

A retrospective observational study was performed including all cases of acute lacosamide poisoning referred to Pavia Poison Control Centre from January 2012 to December 2021. For each patient age, sex, ingested dose, coingestants, clinical manifestations, treatment and outcome were collected.

A total of 31 subjects (median age 39 years, [interquartile range: 26.5-46.5]; females 22/31) were included. The median lacosamide ingested dose was 1500 mg [650-2800]. In 35.5% of cases lacosamide was the single ingested substance, while in 64.5% coingestants were also present. Coingestants varied from a minimum of 1 to a maximum of 3, with the more common being benzodiazepines and valproic acid. Clinical manifestations were present in 87% patients the most common were: vomiting (29%); seizures (29%), coma (25.8%), drowsiness (25.8%), confusion (12.9%), agitation (12.9%), tachycardia (12.9%), tremors (9.7%), bradycardia (9.7%), headache (6.5%) and hypertension (3.2%). The median lacosamide ingested dose was significantly higher in patients that experienced coma compared to patient who did not (2800 vs. 800 mg; P = .0082). Orotracheal intubation was necessary in 32.3% of patients. All patients fully recovered.

Lacosamide acute overdose may lead to a severe clinical picture. Dentral nervous system symptoms predominated, particularly seizures and coma occurred in a high percentage of cases.