Tamlusosin (flomax) has been known to cause retrograde elaculation or dry climax wherein the sperm ejaculates into the bladder instead of being ejected through the urethral opening.
Since patients on treatment for BPH with Flomax have developed this condition as as side effect, it will be addressed appropriately by your urologist.
It is likely that you will be asked to discontinue this medication while being transferred to another drug.
Discontinuing flomax will result in restoration of normal climax with ejaculation if the drug is indeed the cause of the problem.
Do discuss this matter with your urologist.
If you are not concerned about fertility, it is not a condition that requires immediate attention.
Do keep us posted on yout doubts and progress