The generically named medication tamsulosin is marketed in the United States with the brand name Flomax. It is prescribed in the treatment of BPH or benign prostatic hyperplasia, the medical term for noncancerous prostate enlargement. The drug works by making the prostate relax so it does not impinge upon the bladder. The Mayo Clinic says that Flomax does not reduce the prostate's size, but it does improve urination. Sexual side effects of the drug are not that common.
The most serious sexual side effect of taking Flomax, though rare, is that can cause you to have an erection of the penis for longer than normal. This problem can be very painful, and requires a physician's immediate attention.
Flomax may cause the common side effect of problems with your ejaculation during sex. It may, for example, make it take longer than normal to ejaculate. It also may change the way you ejaculate--semen may not be discharged at orgasm. This side effect, while common, is not serious. The Mayo Clinic states it should be temporary in most men, lasting only a few days to a week. If it continues beyond this period, seek advice from your physician.
Sexual Ability Problems
Taking Flomax also may cause a reduction in your normal ability to perform sexual activities, Drugs.com reports, meaning you may perform with less vigor or for a shorter period of time. It also can mean you simply do not perform the same as you normally do. You may, for example, lose your erection in the middle of sexual intercourse or other sexual activity. A less common side effect is impotence or being unable to get or stay erect. These side effects should be temporary in most men.
When you start taking Flomax, your interest in sex may decrease significantly. This is disconcerting for many men, but this reduction in your sexual interest should be temporary, lasting only a few days to a week, according to the Mayo Clinic. Tell your physician if this problem continues.