Inclusion Criteria:  All male patients >=60 years old who undergo inpatient thoracic surgery for major resections.  Exclusion Criteria:  - Prisoners Adults unable to consent End stage renal disease on hemodialysis Indwelling urinary catheter Child-Pugh class C hepatic failure Usage of the following medications prior to surgery: strong CYP 3A4 inhibitors, strong CYP2D6 inhibitors, other alpha-adrenergic blocking agents, PDE5 inhibitors, and cimetidine patients known to be CYP2D6 poor metabolizers History of prostatectomy or cystectomy Patients with contraindications to tamsulosin and those at high risk for side effects: hypersensitivity to tamsulosin HCl or any component of FLOMAX capsules, hypersensitivity to sulfonamides. History of known glaucoma, hypotension, plan to undergo cataract surgery in the next 2 weeks