Treating erectile dysfunction (ED). It may also be used for other conditions as determined by your doctor.
Viagra is a phosphodiesterase inhibitor. It works by helping to increase blood flow into the penis during sexual stimulation. This helps you to achieve and maintain an erection.
Do NOT use Viagra if:
* you are allergic to any ingredient in Viagra
* you have been advised by your doctor to avoid sexual activity because of heart problems
* you are taking nitrates (eg, isosorbide, nitroglycerin) in any form (eg, tablet, capsule, patch, ointment) or nitroprusside
* you use certain recreational drugs called “poppers” (eg, amyl nitrate, butyl nitrate)
Contact your doctor or health care provider right away if any of these apply to you.
Before using Viagra :
Some medical conditions may interact with Viagra . Tell your doctor or pharmacist if you have any medical conditions, especially if any of the following apply to you:
* if you are taking any prescription or nonprescription medicine, herbal preparation, or dietary supplement
* if you have allergies to medicines, foods, or...