Flomax is an alpha-blocker used to treat urination issues such as urgent urination, frequent urination and weak stream in men with benign prostatic hyperplasia, states WebMD. Flomax relaxes muscles in the prostate and bladder, but it does not shrink the prostate.
Flomax may also be used to treat bladder issues in women and kidney stones, explains WebMD. Flomax is taken orally, and it is typically taken once daily. Common Flomax side effects include lightheadedness, dizziness, ejaculation issues and drowsiness. Serious side effects include fainting, prolonged erection and serious allergic reactions such as trouble breathing, rash, itching, swelling and severe dizziness.