Drug-induced xerostomia and hyposalivation in patients with overactive bladder: a prospective open-label observational study comparing antimuscarinics and β3-adrenoceptor agonists.

Drug-induced xerostomia significantly affects quality of life. This study evaluated subjective and objective oral dryness in 101 patients with overactive bladder (OAB) receiving solifenacin (5 or 10 mg) or mirabegron (50 mg). Fox and Xerostomia Inventory questionnaires assessed subjective xerostomia, while unstimulated salivary flow measured objective changes. Overall, salivary flow declined from 0.35 to 0.27 ml/min (- 15.1%; p < 0.001), with the greatest reduction in the solifenacin 10 mg group (- 19.3%; p < 0.001). Mirabegron had a minimal, non-significant impact (- 5.9%; p = 0.42). Hyposalivation prevalence rose from 12.9% pre-treatment to 25.7% post-therapy (p < 0.001), especially among solifenacin users. Men had higher baseline salivation (0.45 vs. 0.27 ml/min; p < 0.001), though both sexes experienced comparable proportional decreases. Mirabegron in multivariable analysis markedly reduced the risk of hyposalivation (OR 0.12, 95% CI 0.02-0.90), whereas hypertension increased it six-fold (OR 6.13, 95% CI 1.02-36.78); each additional 0.1 mL of baseline saliva independently decreased the odds (OR 0.32, 95% CI 0.27-0.38). These findings underscore the need for collaboration among urologists, dentists, and otolaryngologists to identify high-risk individuals early and implement preventive strategies. Adjusting OAB pharmacotherapy regimens may help optimize treatment efficacy while minimizing xerostomia's detrimental impact on oral health and patient quality of life.