Contraindicantions

Do not start or stop any medicine without doctor or pharmacist approval. Inform your doctor about any other medical conditions including penis problems, history of painful or prolonged erection, sickle cell anemia, blood system cancers (such as leukemia or myeloma), vision problems (such as retinitis pigmentosa) or a history of vision loss, kidney or liver disease, bleeding disorders, active stomach ulcers, heart problems, irregular heartbeat, stroke, very high or low blood pressure, or allergies.

Do not take Viagra if you have been told by your healthcare provider to not have sexual activity because of certain health problems, especially heart problems. Don't use Viagra when you are already using nitroglycerin, (such as tablet, patch, or ointment dose forms) or other nitrates (such as isosorbide), nitroprusside (or any "nitric oxide donor" medicine), or recreational drugs called "poppers" containing amyl or butyl nitrate because very serious interactions may occur.