Comparison and Analysis of Delirium Induced by Histamine H2 Receptor Antagonists and Proton Pump Inhibitors in Cancer Patients

Objective: H-2 blockers have been reported to be responsible for drug-induced delirium. We compared the incidence of delirium between two groups of patients who were treated with H-2 blockers (H-2 group) or proton pump inhibitors (PPI group) for anastomotic ulcer prevention following surgical treatment of esophageal cancer. Method: The incidence and severity of delirium were retrospectively compared in patients of the H-2 group (30 cases; age, 65.2 +/- 8.1 years) and the PPI group (30 cases; 65.2 +/- 6.5 years). The diagnosis of delirium was based on the Diagnostic and Statistical Manual of Mental Disorders-IV-Text Revision. Delirium severity was rated on the Delirium Rating Scale (DRS). Results: The incidence of delirium was significantly lower in the PPI group than in the H-2 group (p = 0.047). In the 11 patients from the H-2 group who developed delirium, discontinuation of H-2 blockers resulted in a significant reduction in the DRS score (p = 0.009). In three patients for whom H-2 blockers were discontinued, DRS scores decreased by 50% or more three days after discontinuation compared to the prediscontinuation score. Conclusions: These results suggested that switching antiulcer drugs from H-2 blockers to PPIs reduced delirium and thus provided an appropriate coping method for drug-induced delirium from antiulcer drugs.