Tamsulosin-d4 ((R)-(-)-YM12617 (free base)-d4) is deuterium labeled Tamsulosin. Tamsulosin ((R)-(-)-YM12617 free base) is an inhibitor of alpha1-adrenergic receptor. Tamsulosin is used for the research of prostatic hyperplasia. Tamsulosin attenuates abdominal aortic aneurysm growth in animal models[1][2].