benign prostatic hyperplasia
"I am 73, but an active man.  I suffer from not being able to empty my bladder due to an enlarged prostrate.  My new doctor put me on tamsulosin and it improved my urine flow, but not a massive difference to the number of times I need to urinate in a day, but I thought any improvement was worthwhile.  However, I noticed the last few times I had sex, the feeling I had with ejaculation seemed to diminish until now I have no sensual feeling at all, although it has not affected my drive or erection.  Having read some of the other comments, it seems that this drug is the culprit.  I think I will have to stop taking it and see if there is something else that might work."