Zinc Supplementation With Botulinum Toxin for Overactive Bladder

BACKGROUND AND RATIONALE Intradetrusor botulinum toxin injection is an established treatment for overactive bladder (OAB) refractory to behavioral and pharmacologic therapy. However, duration of therapeutic effect varies among patients, and repeat injections are frequently required. Botulinum toxin activity depends on enzymatic cleavage of synaptic proteins involved in acetylcholine release, and zinc is a cofactor that may influence toxin activity. Phytase may enhance zinc bioavailability by improving intestinal absorption. This study evaluates whether short-course oral zinc plus phytase supplementation administered prior to intradetrusor botulinum toxin injection alters clinical response to treatment. STUDY OBJECTIVES Primary Objective: To determine whether oral zinc plus phytase supplementation prior to intradetrusor botulinum toxin injection reduces the proportion of patients requiring repeat intradetrusor botulinum toxin treatment within 6 months. Secondary Objectives: * To evaluate whether zinc plus phytase supplementation reduces urgency urinary incontinence episodes compared with placebo. * To evaluate changes in overactive bladder symptom severity and patient-reported outcomes following treatment. * To evaluate duration of clinical response following intradetrusor botulinum toxin injection. * To evaluate safety and tolerability of short-course zinc plus phytase supplementation in this population. STUDY DESIGN This is a prospective, randomized, double-blind, placebo-controlled trial. Participants with overactive bladder who are scheduled to undergo intradetrusor botulinum toxin injection as part of routine clinical care will be enrolled and randomized in a 1:1 ratio to receive either: * Oral zinc plus phytase supplementation, or * Matching placebo Study medication will be administered for five days prior to the scheduled intradetrusor botulinum toxin injection. Participants, investigators, and study personnel involved in outcome assessment will remain blinded to treatment assignment. STUDY PROCEDURES Participants will undergo intradetrusor botulinum toxin injection according to standard clinical practice. Following injection, participants will complete remote follow-up assessments every four weeks for six months. Assessments will include: * Bladder diaries * Urinary symptom questionnaires * Patient-reported outcome measures * Assessment of retreatment status