Why does sperm output diminish when you're taking flomax (tamsulosin)?

Actually doesnt: Alpha blocker drugs used for prostatic enlargement such as Flomax cause what is commonly known as retrograde ejaculation. Semen is still produced but it takes the path of least resistance backwards into the bladder rather than forwards during ejaculation. Stopping the drug for 1 to 2 days will generally result in return of ejaculated semen