Urethral obstruction (UO) is a common emergency in male cats, having many causes, and although life-threatening, is treatable with appropriate care. There is a high percentage of recurrent urethral obstruction (rUO), defined as the presence of a non-expressible bladder or observed as non-productive straining to urinate as documented by a veterinarian. Most cases of rUO occur within 2 weeks of discharge and can lead to the need for reconstructive surgery or euthanasia. Prazosin is one of several bladder relaxing drugs used by veterinarians to help treat rUO but there are no controlled clinical studies evaluating the drug in management of feline UO and its use is not considered standard of care at all institutions. This study is a clinical trial evaluating rUO rates in cats treated with a standardized protocol, receiving either prazosin or a placebo (inactive drug) for 7 days following initial presentation. The goal of this study is to provide valuable information regarding the role of prazosin in prevention of short-term rUO and will help guide its use in future cases, perhaps reducing the need for reconstructive surgical procedures and euthanasia.