A Study to Determine the Preferred Dose of the Drug, Lisinopril, for Preventing Urinary Toxicity Following Radiotherapy for Prostate Cancer

This study is finding the best dose of lisinopril — a blood pressure medication — to prevent urinary side effects (like urgency, frequency, or pain) caused by radiation therapy for prostate cancer. **You may be eligible if...** - You are 18 to under 70 years old with confirmed prostate adenocarcinoma - You are scheduled to receive external beam radiation therapy to the prostate (as primary, adjuvant, or salvage treatment), possibly with hormone therapy - Your cancer has not spread to distant organs (stage M0) - You can read English - Your kidney function, blood counts, and liver function are adequate - Your resting systolic blood pressure is above 130 mmHg **You may NOT be eligible if...** - You have had prior pelvic radiation therapy - You are currently taking lisinopril or a similar blood pressure medication (ACE inhibitor or ARB) within the last 2 months - You have had a prior allergic reaction to lisinopril Talk to your doctor to see if this trial is right for you.