A Dose-finding Study of Silodosin in Patients With Urinary Calculi

Inclusion Criteria: * Patients who have a unilateral ureteral calculus with ≥ 5 mm and ≤ 10 mm at Week 0. * Patients who are able to visit the site continually as out-patient during the study Exclusion Criteria: * Patients who have multiple urethral stones. * Patients who have or have history of a ureteral stricture or other structural passage obstruction of the ureter on affected side. * Patients who have been diagnosed with myasthenia gravis, myopathy, spina bifida, spinal cord injury, or fibromyalgia syndrome. * Patients who have a clinically significant hepatic or renal disorder. * Patients with postural hypotension or with a history of postural hypotension. * Patients with a history of sever drug allergy, or patients with a history of hypersensitivity to silodosin. * Patients who are pregnant, nursing, or desire pregnancy during the study period, or patients who cannot strictly comply with a physician's contraception directions.