Case Report: High-dose pregabalin ingestion in an adolescent: clinical course and serial plasma concentrations

Pregabalin (PGB) is widely used for neuropathic pain, generalized anxiety disorder, and seizure management; however, recent epidemiological data highlight a progressive increase in its misuse and involvement in intoxications, particularly among adolescents and individuals with psychiatric comorbidities. Although dose-toxicity relationships have been explored in adult populations, substantial interindividual variability persists, and data in pediatric or adolescent patients remain limited. Establishing clearer associations between ingested dose, serum concentrations, and clinical severity is essential to guide management strategies and identify cases requiring advanced interventions such as extracorporeal removal.

We describe the case of a 16-year-old girl who intentionally ingested 2,700 mg (54 mg/kg, based on the patient's body weight of 51 kg) of immediate-release pregabalin. She presented at the Emergency Care Unit 10 h after ingestion with marked somnolence, psychomotor slowing, and bilateral horizontal nystagmus, while vital signs, renal and hepatic function tests remained normal. Electrocardiography revealed only mild PR interval prolongation. Serial plasma concentrations of Pregabalin demonstrated a decline from 16.5 mg/L at 12 h to 8.4 mg/L at 18 h and 0.69 mg/L at 34 h, consistent with expected pharmacokinetics. No gastrointestinal decontamination was performed due to delayed presentation, and no extracorporeal treatments were deemed necessary. Patient was subjected to a clinical conservative management, and progressively recovered without neurological sequelae.

Despite ingestion of a dose commonly associated with moderate to severe toxicity, the patient exhibited a mild and self-limited clinical course, emphasizing the variability of pregabalin toxicity in adolescents. Clinical assessment remains the primary guide, while serum concentrations provide supportive information when available.