Flomax (OMNIC - BRAND) is in a group of drugs called alpha-adrenergic (AL-fa ad-ren-ER-jik) blockers. Flomax relaxes your veins and arteries so that blood can more easily pass through them. It also relaxes the muscles in the prostate and bladder neck, making it easier to urinate. Flomax is used to improve urination in men with benign prostatic hyperplasia (enlarged prostate).