New-Onset Seizure Following Loratadine and Alcohol Ingestion: A Case Report

Loratadine is a common over-the-counter second-generation H1-antihistamine used to relieve and treat seasonal allergy symptoms. While first-generation H1-antihistamines are historically known to cause central nervous system (CNS) side effects, these effects are thought to be far less common in second-generation antihistamines. Similarly, alcohol is known to have CNS effects. We report a case of a 26-year-old female who presented to the emergency department (ED) after a suicide attempt involving loratadine and alcohol ingestion. Emergency medical services (EMS) reported that the patient became unresponsive upon arrival at the ED. An empty loratadine bottle that was supposed to contain 60 tablets was found at the scene. Additionally, an empty bottle of wine was also found at the scene. Initial vital signs and glucose levels were normal, but on examination, the patient had a Glasgow Coma Scale of 3 with rightward eye deviation and developed tonic-clonic seizures, which were quickly controlled with 4 mg of intravenous (IV) lorazepam. She gradually regained responsiveness and received 3200 mg of levetiracetam IV. Toxicological workup revealed a serum ethanol level of 119 mg/dL and a urine toxicology screen positive for benzodiazepines, likely due to lorazepam administration. The patient had mildly elevated lactate and creatine kinase levels consistent with seizure, which normalized after fluid resuscitation. The patient recovered fully without further seizures and was not prescribed antiepileptic medication upon discharge. We present the case to document a potential seizure provoked by the combined ingestion of loratadine and alcohol.