Omeprazole-induced Visual Hallucinations: A Case Report

Evidence for Metabolic Activation of Omeprazole In Vitro and In Vivo

Omeprazole (OPZ) is a proton pump inhibitor commonly used for the treatment of gastric acid hypersecretion. Studies have revealed that use of OPZ can induce hepatotoxicity, but the mechanisms by which it induces liver injury are unclear. This study aimed to identify reactive metabolites of OPZ, determine the pathways of the metabolic activation, and define the correlation of the bioactivation with OPZ cytotoxicity. Quinone imine-derived glutathione (GSH), N-acetylcysteine (NAC), and cysteine (Cys) conjugates were detected in OPZ-fortified rat and human liver microsomal incubations captured with GSH, NAC, or Cys. The same GSH conjugates were detected in bile of rats and cultured liver primary cells after exposure to OPZ. Similarly, the same NAC conjugates were detected in urine of OPZ-treated rats. The resulting quinone imine was found to react with Cys residues of hepatic protein. CYP3A4 dominated the metabolic activation of OPZ. Exposure to OPZ resulted in decreased cell survival in cultured primary hepatocytes. Pretreatment with ketoconazole attenuated the susceptibility of hepatocytes to the cytotoxicity of OPZ.

Commentary: Psychiatric Presentations of Nonpsychiatric Illness or Treatment

Patients presenting with psychiatric symptoms, even in cases where there is no clear psychiatric history, are often labeled as having "psychogenic" symptoms or a psychosomatic reaction, and a tendency does exist to mislabel and/or misdiagnose certain patients in medical settings. The 3 cases presented in this issue of the Journal provide examples of patients presenting with psychotic or manic symptoms in the context of an underlying nonpsychiatric medical disorder. Kim and colleagues describe the case of a 65-year-old man with no psychiatric history who presented with acute visual hallucinations 1 day after starting omeprazole for gastroesophageal reflux. The visual hallucinations resolved immediately after the medication was stopped. Fipps and Rainey describe the case of a 74-year-old man with chronic generalized anxiety who presented with severe panic and suicidal thinking as well as refractory nausea that were unresponsive to benzodiazepine treatment and to a taper of the benzodiazepine. This patient was later found to have a subdural hematoma that was causing what had at first been suspected to be psychogenic nausea. Finally, Das and Brasseux present the case of a 23-year-old man hospitalized from jail who presented with manic symptoms; this patient was found to have had a traumatic brain injury 2 months earlier and, on brain imaging, was also found to have had a perinatal brain injury. The patient responded to mood stabilizers and the off-label use of memantine for his cognitive deficits. These 3 cases highlight the importance of obtaining a comprehensive neurological and medical history and, if indicated, workup, in cases involving patients with atypical presentations or nonresponse to traditional treatments.