Hello Thanks for query . You have been detected to have kidney stone and your Dr has prescribed you medication for the same . Normally it is Tomsulosin that is prescribed in treatment of Kidney stone . Tomsulosin is a smooth muscle relaxant and it relaxes smooth muscle in ureter and bladder neck .This results into bladder neck to remain wide open that causes semen to enter backwards into bladder instead of moving forward in to urethra reresulting into dry ejaculation .This is called as Retrograde Ejaculation . There is nothing to be worried about it ,Ejaculation will get restored once you stop taking Tomsulosin . Dr.Patil.