Tadalafil is used to treat erectile dysfunction, a condition where you are unable to get or keep an erection firm enough to have sexual intercourse. It works by relaxing the blood vessels in your penis, allowing blood to flow into your penis when you get sexually excited. This medicine will only help you to get an erection if you are sexually stimulated. Therefore it is taken on an as-needed basis.
It can also be used for urinary symptoms associated with benign prostatic hyperplasia (enlarged prostate) with or without erectile dysfunction at the same time. It improves blood flow to, and relaxes the muscles of the prostate and bladder which may reduce symptoms of benign prostatic hyperplasia. For this indication, it has to be taken on a daily basis.
This medication may also be used for other conditions. Check with your healthcare professional if you are unsure why you are given this medication.