Effects of Orexin Receptor Antagonists on Nocturia and Overactive Bladder Symptoms in Patients with Insomnia: A Single-Center Retrospective Study.

Purpose: Although orexin receptor antagonists (ORAs) are widely prescribed for insomnia, experimental studies have suggested that these agents may prolong intervals between bladder contractions. This study investigated the hypothesis-generating associations between ORA treatment and improvements in nocturia and overactive bladder symptoms in patients with insomnia. Methods: Enrolled were 45 patients who visited our hospital between September 2022 and December 2025 with nocturia as their main complaint and experienced two or more nighttime urinations. All had overactive bladder symptoms defined as a urinary urgency score ≥2 and total score ≥3 based on the Overactive Bladder Symptom Score (OABSS), as well as insomnia. They were treated with ORAs for 4 weeks, with OABSS scores and postvoid residual urine volume evaluated before and 4 weeks after starting treatment. Results: There were 39 males and 6 females, with a mean age of 76.2 years. Overactive bladder severity was categorized as mild in 5 patients, moderate in 35, and severe in 5. The total OABSS score decreased significantly following ORA treatment, from 8.1 to 6.2 (P <0.001). Analysis of each OABSS domain showed significant reductions in daytime frequency (1.1 to 0.9, P <0.05), nighttime frequency (2.8 to 2.2, P <0.001), urgency score (3.0 to 2.1, P <0.001), and urge urinary incontinence (1.2 to 0.9, P <0.01) scores. In contrast, postvoid residual urine volume did not increase significantly after treatment (P = 0.83). Conclusions: ORA treatment was found to be effective and safe in insomnia patients with nocturia. The findings suggest that ORAs may improve nocturia and OAB symptoms in patients with insomnia.