A recent randomized clinical trial has assessed the efficacy of suvorexant in reducing delirium in older adults. The study, conducted across 50 Japanese hospitals, included 203 participants aged 65 to 90 years who were at high risk for delirium after hospitalization for sudden illness or scheduled surgery. While the overall reduction in delirium was not statistically significant, post-hoc analysis suggested a potential benefit in managing hyperactive and mixed delirium subtypes.
Study Design and Methodology
The double-blind, placebo-controlled, phase 3 trial, which took place from October 2020 to December 2022, randomly assigned participants to receive either suvorexant (15 mg) or a placebo each night for five to seven days. Delirium was assessed daily based on the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition criteria. Subtypes of delirium—hyperactive, hypoactive, and mixed—were also recorded.
Key Findings
While suvorexant showed a trend toward reducing delirium (16.8% vs. 26.5% in the placebo group), the difference was not statistically significant. The incidence of hypoactive delirium was similar in both groups (5.9% in the suvorexant group and 4.9% in the placebo group). However, the incidence of hyperactive and mixed delirium was lower in the suvorexant group (10.9%) compared to the placebo group (21.6%).
Implications and Context
Professor Kotaro Hatta from Juntendo University Nerima Hospital, a key researcher in the study, noted that the lack of significant overall reduction in delirium was surprising, given positive findings in previous studies. He suggested that those studies may have focused more on hyperactive or mixed delirium, overlooking hypoactive delirium. "Addressing this issue can increase the life expectancy of older adults and reduce the burden on health care providers," Hatta stated.
Delirium is a common and serious issue among older hospitalized adults, increasing the risk of falls, dementia, and low life expectancy. Non-pharmacological approaches are often time-consuming and only partially effective, making pharmacological interventions a promising avenue. Suvorexant, an orexin receptor antagonist, promotes sleep by blocking orexin, a neuropeptide that regulates wakefulness. This mechanism could potentially prevent delirium, particularly hyperactive and mixed subtypes, which are especially burdensome for hospital staff due to the agitation, hallucination, and impulsivity associated with them.
