Urolithiasis is a disease that effects 12% of the population and its incidence is growing. In the US there are over 1.1 million visits annually to Emergency Departments for renal colic. The disease is extremely painful, often requiring large amounts of narcotic analgesia, and results in lost work days. Moreover, up to 30% of patients may eventually require lithotripsy or surgical removal of the stone. Currently there are no medical interventions other than analgesia which are offered to patients.

Based on encouraging results from several small European clinical studies, the researchers hypothesize that the administration of tamsulosin to patients with symptomatic urolithiasis will enhance stone passage, and reduce both the time to recovery and the need for surgical intervention or lithotripsy. The researchers will conduct a study by identifying and recruiting patients presenting with urolithiasis in the emergency departments of four institutions.

A total of 500 consenting subjects will be randomly assigned to one of two groups:

1. tamsulosin for a maximum of 28 days;
2. placebo for a maximum of 28 days.

In addition, both groups will receive standard analgesic therapy.

The study team, which will be blinded to treatment status, will monitor each subject's clinical progress and outcome. The primary objectives of this study are:

1. to determine if tamsulosin is effective, and
2. to evaluate the safety of the therapy.

Another objective is to identify the most appropriate clinical subgroup(s) for treatment.

If the therapeutic benefits observed in smaller clinical studies are replicated, administration of these medications should produce several benefits, including:

1. a reduction in time to pain free recovery and hence a more rapid return to employment;
2. decreased requirements for narcotic analgesia;
3. less need for urological out-patient clinic follow-up;
4. decreased need for surgical intervention or lithotripsy; and
5. substantial cost savings.

If this therapy is beneficial, it will represent a major advance in the treatment of urolithiasis. This objective is a major stated goal of the NIDDK (National Institute of Diabetes and Digestive and Kidney Diseases) Clinical Urology Program, which has a stated mission to improve the treatment of urolithiasis.

Kidney stones are a major public health issue, and one person in eight will be affected by the disease. If the hypothesis is verified, the researchers will provide the first medical therapy ever for this disease. This therapy, if effective, will reduce the amount of time a patient is off work because of the pain from the disease, and may also reduce the need for expensive and time-consuming surgical treatments.

Inclusion Criteria:

1. Age ≥ 18 years
2. Evidence of ureterolithiasis (i.e. stone is located in ureter, not in bladder) as demonstrated on radiographic studies, specifically non-contrast spiral CT.
3. Willingness to participate and able to proceed with standard outpatient management (no personal or job-related issues, e.g. airline pilot.
4. Has a telephone in order to be contacted for follow-up.

Exclusion Criteria:

1. Patient desiring or requiring immediate surgical intervention making then not a candidate for outpatient kidney stone management.
2. Current urinary tract infection based on urine dipstick as admission and urgent procedural management are likely indicated.
3. Known anatomical genitourinary abnormalities or prior Genitourinary surgeries.
4. Positive pregnancy test making proper radiological imaging contraindicated.
5. Breastfeeding mothers.
6. History of hypersensitivity to tamsulosin.
7. Current use of alpha blockers or calcium channel blockers.
8. Current use of steroids which may have an independent effect on stone expulsion.
9. Spontaneous stone expulsion prior to enrollment.
10. Largest stone dimension ≥ 9mm assessed using radiologic imaging, being very unlikely to pass spontaneously.
11. Presence of stone in the bladder.
12. Current use of vardenafil which is tamsulosin contraindicated.
13. Ipsilateral, transplanted or solitary kidney as hospitalization may be necessary.
14. Known renal insufficiency.
15. Fever defined as >101.5°F which may indicate infection.
16. Floppy iris syndrome which is tamsulosin contraindicated.
17. Planned cataract surgery in the next 60 days which is tamsulosin contraindicated.
18. Prisoners /wards of state.
19. Prior enrollment in STONE (Candidates who are screened and found ineligible may be rescreened at a later date.)

Adverse event data were collected for 90 days after each patient enrollment in the study.