Medical Information What Viagra is NOT It is not an aphrodisiac; you need to be aroused or stimulated by your partner. If you are not aroused or stimulated as in normal sex nothing will happen. However, when aroused it will facilitate sufficient blood flow into the smooth muscle of the penis and cause it to be held there, thus maintaining a full erection just as your own body would. The medication will stay in your body for several hours allowing you to have sex again if you so desire. Who Can Take It? After a medical assessment by the doctor, the majority of men. Who Can NOT Take It? If you are on ANY form of Nitrate medication you will not be suitable, e.g. for angina or certain heart conditions. Viagra is not indicated for individuals below twenty three years of age.