Post-Operative Urinary Retention (POUR) in Thoracic Surgery Patients Receiving Prophylactic Tamsulosin

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