Here is the design of a clinical trial:

Official Title: Randomized, Quadruple Blinded, Placebo Controlled, Multi-centered Trial Investigating Prophylactic Tamsulosin in Prevention of Postoperative Urinary Retention in Men After Endoscopic Total Extraperitoneal Inguinal Hernia Repair

Included conditions:
- Urinary Retention
- Inguinal Hernia

Study Armgroups:
- {'label': 'Tamsulosin Arm', 'type': 'EXPERIMENTAL', 'description': 'p.o.', 'interventionNames': ['Drug: TAMSULOSIN Mepha Ret Depocaps 0.4 mg']}
- {'label': 'Placebo Arm', 'type': 'PLACEBO_COMPARATOR', 'description': 'p.o.', 'interventionNames': ['Drug: Control Intervention']}

Interventions:
- {'type': 'DRUG', 'name': 'TAMSULOSIN Mepha Ret Depocaps 0.4 mg', 'description': '0.4mg/day Tamsulosin hydrochloride ("TAMSULOSIN Mepha Ret Depocaps 0.4 mg") from 5 days prior to the day of surgery, at the day of surgery and for 1 day following surgery. (5+1+1)', 'armGroupLabels': ['Tamsulosin Arm'], 'otherNames': ['Verum']}
- {'type': 'DRUG', 'name': 'Control Intervention', 'description': 'One placebo capsule matching the active study drug per day from 5 days prior to the day of surgery, at the day of surgery and for 1 day following surgery. (5+1+1)', 'armGroupLabels': ['Placebo Arm'], 'otherNames': ['Placebo']}

Primary Outcomes:
- {'measure': 'Post operative urinary retention (Need for any catheterization postoperatively)', 'description': 'Need for any catheterization postoperatively (Yes/No)', 'timeFrame': 'up to 3 days after surgery'}

Please estimate the sample size based on the assumption: 
80% study power, 5% significance level, 2% dropout rate
Sample size
          We anticipate the detection of a 65% relative risk reduction of POUR in the experimental group in comparison with the placebo group, based on conservative assumptions from previous publications.5â7 To detect a 65% reduction of POUR in the experimental group (2.9% anticipated) in comparison with the placebo group (8.3% anticipated) and to assure a study power of 80% with a Fisherâs exact test and a significance level of 5% and adjusting for a dropout rate of 2% we need 634 patients in total; 317 in each group.