Tamsulosin Capsules 0.4mg 10'sTamsulosin 0. 4mg is used in men to treat the symptoms of an enlarged prostate (benign prostatic hyperplasia or BPH) which include difficulty urinating (hesitation, dribbling, weak stream, and incomplete bladder emptying), painful urination, and urinary frequency and urgency. Tamsulosin 0. 4mg is in a class of medications called alpha blockers. It works by relaxing the muscles in the prostate and bladder so that urine can flow easily. Dose Tamsulosin