Effect of Antimuscarinic Treatment on Premature Ejaculation Severity in Men With Overactive Bladder: a Prospective Comparison With Mirabegron

Başakşehir Çam & Sakura City Hospital40 enrolled

Overview

Overactive bladder (OAB) is a condition characterized by involuntary bladder contractions. Antimuscarinic drugs are commonly used to treat OAB by blocking muscarinic receptors (M2 and M3) in the bladder. These same receptors are also present in the seminal vesicles and vas deferens, which are structures involved in ejaculation. This observational study aims to evaluate whether antimuscarinic drugs used for OAB treatment have any effect on ejaculation duration and the refractory period in male patients. Male patients aged 20-50 who are prescribed antimuscarinic medication (tolterodine, propiverine) for OAB will complete validated questionnaires (IIEF, PEP, PEDT, OAB-V8) before starting treatment and at 1-month and 2-month follow-up visits. No changes will be made to the patients' standard treatment.

Overactive bladder affects quality of life significantly and is managed with antimuscarinic agents that block M2 and M3 muscarinic receptors. M3 receptors mediate direct smooth muscle contraction via Gq protein and phospholipase C-induced calcium release, while M2 receptors modulate M3 activity indirectly via Gi protein and adenylyl cyclase inhibition. Ejaculation consists of two phases: emission (peristaltic movement of seminal fluid from seminal vesicles and vas deferens into the prostatic urethra) and expulsion (forceful ejection from the urethra). Both M2 and M3 receptors have been identified in smooth muscle and epithelial cells of seminal vesicles in animal studies, suggesting a role in regulating peristaltic contractions during the emission phase. This study hypothesizes that antimuscarinic drugs may prolong ejaculation duration by inhibiting peristaltic activity in the seminal vesicles and vas deferens via M2/M3 receptor blockade, thereby extending the emission phase. Male patients aged 20-50 presenting with OAB symptoms and initiated on antimuscarinic therapy will be evaluated using IIEF, PEP, PEDT, and OAB-V8 questionnaires at baseline, 1 month, and 2 months. This is a purely observational study with no modification to standard clinical care.

Study Type

OBSERVATIONAL

Enrollment

Conditions

Overactive Bladder (OAB)

Interventions

TolterodineDRUG

Tolterodine is a competitive muscarinic receptor antagonist with relative functional selectivity for the bladder. It is prescribed as standard clinical care for overactive bladder symptoms. Dose and formulation are determined by the treating physician per routine practice. No modification to the prescribed regimen is made within the scope of this observational study.

Mirabegron (beta3-adrenoceptor agonist)DRUG

Mirabegron is a beta-3 adrenergic receptor agonist used for overactive bladder treatment. Unlike antimuscarinic agents, it does not block muscarinic receptors. It is included in this study as a comparison group to evaluate whether ejaculatory effects are specific to muscarinic receptor blockade. Prescribed as standard clinical care with no modification to treatment.

Eligibility

Sex: MALEMin age: 20 YearsMax age: 50 Years

Medical Language ↔ Plain English

Inclusion Criteria: * Male patients aged 20-50 years * Diagnosis of overactive bladder (OAB) confirmed clinically * Sexually active * Willing to complete questionnaires at all three time points Exclusion Criteria: * Previous use of antimuscarinic or beta-3 agonist medications * Neurological disorders affecting bladder or sexual function (e.g., multiple sclerosis, Parkinson's disease, spinal cord injury) * Prior pelvic surgery or radiotherapy * Use of medications known to affect ejaculatory function (e.g., alpha-blockers, SSRIs, antipsychotics) * Active urinary tract infection * Uncontrolled diabetes mellitus * Unwillingness to participate

Outcomes

Primary Outcomes

Change in Ejaculatory Function as Assessed by PEDT

Change in premature ejaculation severity from baseline to follow-up visits, evaluated using the Premature Ejaculation Diagnostic Tool (PEDT). PEDT (Premature Ejaculation Diagnostic Tool) 5 questions, 0-4 points each, total 0-20. Score ≤8: no PE, 9-10: borderline, ≥11: premature ejaculation.

Time frame: Baseline, 1 month, and 2 months

Secondary Outcomes

Change in Overactive Bladder Symptoms as Assessed by OAB-V8

Change in overactive bladder symptom severity from baseline to follow-up visits, evaluated using the OAB-V8 questionnaire. OAB-V8 (Overactive Bladder Questionnaire-V8) 8 questions, 0-5 points each, total 0-40. Score ≥8 indicates clinically significant OAB symptoms.