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.