Only the study team can determine whether someone qualifies for participation.
Inclusion criteria
Age ≥ 18 years (all genders) Confirmed IC/BPS diagnosis fulfilling AUA 2015 and ESSIC standardized diagnostic criteria, ruled out confounding urologic disorders Predominant lower urinary tract symptoms present for most days in the past 3 months Baseline bladder/pelvic pain and urinary frequency score ≥ 3 points on 0-10 Likert scale within prior 4 weeks
Exclusion criteria
Symptomatic urethral stricture Active degenerative/inflammatory neurological disease altering bladder/intestinal function Uncontrolled active autoimmune disease or systemic infection Medical history of pelvic tuberculosis, pelvic radiotherapy or chemotherapy-induced cystitis History of non-cutaneous malignant tumors Current diagnosis of severe psychiatric disorders (major depressive disorder, bipolar disorder, schizophrenia, psychotic disorders) Clinically significant moderate-severe cardiac, pulmonary, hepatic or renal insufficiency Documented hypersensitivity to venlafaxine or other SNRI drugs Concurrent regular use of antibiotics or NSAIDs throughout trial period Pregnancy or breastfeeding state at screening