The goal of this clinical trial is to compare the efficacy and safety of intravesical Botulinum Toxin A versus intravesical Platelet-Rich Plasma (PRP) in adults with refractory overactive bladder who have not responded adequately to conventional medical treatment. The main questions it aims to answer are:

• Whether intravesical PRP is as effective as intravesical Botulinum Toxin A in improving overactive bladder symptoms.
• Whether intravesical PRP has a better safety profile and lower incidence of adverse events during the 2-year follow-up period.

Researchers will compare participants receiving intravesical Botulinum Toxin A with those receiving intravesical PRP to determine differences in symptom improvement, quality of life, urodynamic outcomes, and treatment-related adverse events.

Participants will:

• Receive either intravesical Botulinum Toxin A injection or intravesical Platelet-Rich Plasma injection.
• Undergo baseline clinical assessment, symptom evaluation, and urodynamic studies as indicated.
• Attend scheduled follow-up visits over a 2-year period.
• Complete validated questionnaires assessing overactive bladder symptoms and quality of life.
• Be monitored for treatment efficacy and any adverse events throughout the study.

The purpose of this prospective randomized clinical trial is to compare the efficacy and safety of intravesical Platelet-Rich Plasma (PRP) injection with intravesical Botulinum Toxin A injection in adult patients with refractory overactive bladder (OAB) who have failed or were intolerant to conventional medical therapy. Overactive bladder is a chronic condition characterized by urinary urgency, usually accompanied by increased daytime frequency and nocturia, with or without urgency urinary incontinence, and has a significant negative impact on patients' quality of life.

Botulinum Toxin A is an established third-line treatment for refractory OAB; however, its use may be associated with adverse events such as urinary retention, increased post-void residual urine, and urinary tract infection. Platelet-Rich Plasma has recently emerged as a regenerative therapeutic option because of its anti-inflammatory and tissue-repair properties and may provide symptom improvement with fewer complications.

The primary objective of this study is to compare the improvement in overactive bladder symptoms between the two treatment groups over a 2-year follow-up period. Secondary objectives include comparing quality of life, urinary frequency, urgency episodes, urgency urinary incontinence episodes, nocturia, functional bladder capacity, post-void residual urine volume, patient satisfaction, durability of treatment response, and treatment-related adverse events.

Eligible participants will be randomly assigned to receive either intravesical Botulinum Toxin A injection or intravesical Platelet-Rich Plasma injection according to the study protocol. Baseline assessment will include medical history, physical examination, symptom evaluation using validated questionnaires, voiding diary, laboratory investigations, and other investigations as indicated. Participants will undergo scheduled follow-up visits throughout the 2-year study period to assess clinical response, monitor for adverse events, and evaluate the need for additional treatment.

Inclusion Criteria:

• Adults aged ≥18 years
• Diagnosis of refractory overactive bladder (OAB)
• Failed at least 2 pharmacological therapies
• Willing and able to provide informed consent

Exclusion Criteria:

• Neurogenic bladder
• Active urinary tract infection (UTI)
• Pregnancy or lactation
• Known allergy to botulinum toxin or any PRP components
• History of pelvic radiation or bladder malignancy
• Uncontrolled coagulopathy or bleeding disorder