Naloxone-responsive respiratory depression in a patient with a negative urine drug screen

Abstract A 24-year-old male with a history of dizziness and syncope presented to the emergency department via ambulance for the fourth time in 36 hours. His medical history is significant for postural orthostatic tachycardia and factitious disorder. Upon examination in the emergency department, the patient appeared somnolent and displayed shallow, short breaths with occasional apnea. There was a concern for possible opioid overdose prompting admission to the medical intensive care unit. Laboratory testing demonstrated hypercapnic respiratory failure and a negative urine drug screen. Though the patient’s symptoms resolved upon administration of naloxone he denied ingestion of any substances that would contribute to his condition. Previous medical issues had been attributed to misuse of medications prescribed to the patient and loperamide was discovered in his belongings. Testing confirmed the presence of loperamide at supratherapeutic concentrations in his serum.