Prevention of Post Operative Urinary Retention After Thoracic Surgery Trial

Inclusion Criteria ( 2 or more of the following risk factors): * Male Sex * Age greater than or equal to 40 years * History of Diabetes Mellitus * Prior pelvic irradiation * Use of indwelling Thoracic Epidural analgesia * Prior history of urinary retention AND International Prostate Specific Score greater than or equal to 1. Exclusion Criteria: * Active treatment of Benign Prostatic Hyperplasia (BPH) * Hypersensitivity or allergy to tamsulosin HCL * Active treatment with tamsulosin or other alpha-blocker or uses of tamsulosin/ other alpha-blocker within 3 weeks of enrollment date * Active urinary tract infection * History of urological disorder specified as urethral stricture, BPH, bladder or prostate malignancy. * History of urological surgery (Transurethral resection of the Prostate, Transurethral resection of the Bladder, Bladder suspension, prostatectomy) * Underlying neurological disorders resulting in impaired bladder function * Any known contraindication to the use of tamsulosin HCL * Nursing/ Breastfeeding women * Use of intraoperative bladder catheter * patients for whom cataract and/or glaucoma surgery is scheduled. * patients on strong inhibitors of CYP3A4 (e.g., ketoconazole), on moderate inhibitors of CYP3A4 (e.g., erythromycin), on strong (e.g. paroxetine), on moderate (e.g., terbinafine) inhibitors of CYP2D6 or in patients known to be CYP2D6 poor metabolizers. * patients with a serious or life-threatening sulfa allergy * patients with severe hepatic insufficiency * patients with severe renal impairment (creatinine clearance of \<10 mL/min) * patients with a serious or life-threatening sulfa allergy