Patient description: The patient is a 63-year-old man presenting to the Emergency Department with a history of acute urinary retention in the past 2 days. Abdominopelvic CT scan revealed a large prostate and a bladder filled with urine. He is a candidate for urethral catheterization and TURP. Further evaluation revealed: Post-void residual: 71 mL Prostate volume (TRUS): 63 mL Prostate-specific antigen (PSA) level: 3.5 ng/mL His recent blood chemistry (3 days ago) was normal: Hgb: 13.6 g/dl WBC: 133000 /mm3 Plt: 370000 /ml PT: 12 second PTT: 34 second INR: 0.9 Creatinine: 0.5 mg/dl BUN: 10 mg/dl U/A: Color: yellow Appearance: cloudy PH: 5.3 Specific gravity: 1.010 Glc: 100 Nitrite: negative Ketone: none Leukocyte esterase: negative RBC: negative WBC: 2 WBCs/hpf U/C: negative

Clinical trial eligibility criteria: eligible ages (years): 20.0-45.0,  Prostatic Hyperplasia A subject will be eligible for in this study only if all of the following apply Healthy as determined by a responsible and experienced physician, based on a medical evaluation including medical history, physical examination, laboratory tests and cardiac monitoring. A subject with a clinical abnormality or laboratory parameters outside the reference range for the population being studied may be included only if the Investigator and the GSK Medical Monitor agree that the finding is unlikely to introduce additional risk factors and will not interfere with the study procedures Males between 20 and 45 years of age inclusive, at the time of signing the informed consent form Japanese ancestry defined as being born in Japan, having four ethnic Japanese grandparents, holding a Japanese passport or identity papers and being able to speak Japanese, or Korean ancestry defined as being born in Korea, having four ethnic Korean grandparents, holding a Korean passport or identity papers and being able to speak Korean, or Chinese ancestry defined as being born in China, Hong Kong, Singapore or Taiwan, having four ethnic Chinese grandparents, holding a Chinese passport or identity papers and being able to speak Chinese. Japanese, Korean and Chinese subjects should also have lived outside their respective countries for less than 10 years Male subjects with female partners of child-bearing potential must agree to use one of the protocol-approved contraception methods. This criterion must be followed from the time of the first dose of study medication until 45 days after the last dose BMI within the range 18 -28 kg/m2 (inclusive) Capable of giving written informed consent, which includes compliance with the requirements and restrictions listed in the consent form Single QTc < 450 msec; or QTc < 480 msec in subjects with Bundle Branch Block AST, ALT, alkaline phosphatase and bilirubin less than or equal to 1.5xULN (isolated bilirubin >1.5xULN is acceptable if bilirubin is fractionated and direct bilirubin <35%)  A subject will not be eligible for in this study if any of the following apply: Medical Condition Exclusions Poor metabolizer for CYP2D6 substrates as determined by genotyping of selected CYP2D6 variants at screening History of postural hypotension, dizziness, poor hydration, vertigo, vaso-vagal reactions or any other signs and symptoms of orthostasis, which in the opinion of the investigator could be exacerbated by tamsulosin and result in putting the subject at risk of injury Current or chronic history of liver disease, or known hepatic or biliary abnormalities (with the exception of Gilbert's syndrome or asymptomatic gallstones A positive pre-study Hepatitis B surface antigen or positive Hepatitis C antibody result within 3 months of screening A positive test for HIV antibody. Medical Exclusions Subjects must be able and willing to refrain from use of prescription or non-prescription drugs, including vitamins, herbal and dietary supplements (including St John's Wort, Black Khosh, Dong Quai, Milk Thistle, licorice) within 7 days (or 14 days if the drug is a potential enzyme inducer) or 5 half-lives (whichever is longer) prior to the first dose of study medication, unless in the opinion of the Investigator and GSK Medical Monitor the medication will not interfere with the study procedures or compromise subject safety History of sensitivity to tamsulosin HCl or dutasteride, components thereof or drugs of this class or a history of drug or other allergy that, in the opinion of the investigator or GSK Medical Monitor, contraindicates their participation A history of sensitivity to heparin or heparin-induced thrombocytopenia The subject has participated in a clinical trial and has received an investigational product within the following time period prior to the first dosing day in the current study: 30 days, 5 half-lives or twice the duration of the biological effect of the investigational product (whichever is longer)