Erection production requires a precise sequence of events to take place in your brain and body, beginning with arousal signals sent from the cortex, followed by actions which increase blood flow to your penis – Viagra helps relax muscle walls of blood vessel walls to achieve this, but only works if sexually stimulated, such as during sexual activity.

Take Viagra prior to engaging in sexual activity is the optimal way to maximize its efficacy, as this allows it to start working before you and your partner have sexual encounters. Furthermore, doing this helps avoid an erection lasting more than four hours that can cause pain and damage penis tissue (priapism).

Viagra may cause rare side effects that include an enlarged prostate or decrease in bladder control, so if this occurs it should be reported immediately to your physician. In rare cases, patients taking Viagra have experienced chest pain or irregular heartbeat; to understand your risk properly it’s essential that you discuss this risk with your physician if any history exists of these or similar issues exist in your family history.

Viagra may be taken off-label to treat Raynaud’s disease, a condition in which your blood vessels spasm and narrow, restricting blood flow to your fingertips, leaving them cold, painful or numb. Studies show that taking Viagra or another similar medication may reduce both frequency and length of Raynaud’s episodes.