From Mayo Clinic to your inbox Sign up for free and stay up to date on research advancements, health tips, current health topics, and expertise on managing health. You should only be treated with one of these products at a time. This is a type of high blood pressure that occurs between the heart and the lungs. To provide you with the most relevant and helpful information, and understand which information is beneficial, we may combine your email and site usage information with other information we have about you. Erectile dysfunction is a condition where the penis does not harden and expand when a man is sexually excited, or when he cannot keep an erection. Talk to your doctor about eating grapefruit and drinking grapefruit juice while taking this medicine. · Side effects Interactions FAQ What is sildenafil? Sildenafil relaxes muscles of the blood vessels and increases blood flow to particular areas of the body. Sildenafil .  · Without physical action to the penis, such as that occurring during sexual intercourse, sildenafil will not work to cause an erection. Sildenafil is also used in both Missing: oral jelly. What side effects can this medication cause? What should I know about storage and disposal of this medication? In case of emergency/overdose What other information Missing: oral jelly.