Hi, thanks for using healthcare magic Tamsulosin is one of the more commonly used medications for enlarged prostate. It, like all medications, has potential side effects that may or may not occur. One of the side effects are prolonged erection requiring treatment. Other possible problems are ejaculatory failure or it could take longer for the ejaculation to occur, these possible side effects usually occur in the first few days or weeks after treatment is started. Impotence is a rare complication. If impotence does occur then you can consider speaking to your doctor, he or she may suggest medication that may help It is also important to note that severe BPH can also cause erectile problems. I hope this helps