Randomized clinical study of silodosin vs propiverine for men aged 50 or older with overactivebladder and 20 to 30ml of prostate volume

INTERVENTION: Silodosin (4mg) 1 Capsule or Silodosin (2mg) 2 Capsules 2x1 after breakfast and dinner daily, orally Propiverine (10mg) 1x1 after breakfast daily, orally CONDITION: Overactive bladder PRIMARY OUTCOME: Proportion of patients who need treatment change or discontinuation within 8 weeks SECONDARY OUTCOME: OABSS, I‐PSS total score, QoL index, voiding/storage subscore, maximal flow rate, postvoid residual urine volume (PVR), the ratio of patients with increasing PVR and adverse effect INCLUSION CRITERIA: 1) Men are aged 50 or older. 2) Prostate volume is 20ml or greater and less than 30ml by ultrasonography. 3) Overactive bladder is indicated by OABSS: urgency score 2 or greater and total score 5 or greater 4) Postvoid residual urine is 50ml or less.