Viagra is a medication used to treat Erectile Dysfunction (ED) also known as impotence. Sildenafil (the active ingredient in Viagra) works by increasing blood flow so that the erection can last longer and be stronger. Sildenafil (Revatio) is also used daily in a lower dose to treat pulmonary arterial hypertension (PAH). Viagra tabs are diamond-shaped & blue with the word Pfizer embossed on one side, and VGR engraved on the other. Viagra is taken once a day between 30 minutes and 4 hours prior to sexual intercourse.
Viagra side effects include dizziness, headache, and stomach upset. Vision changes such as increased sensitivity to light, blurred vision, or trouble telling blue and green colors apart may also occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly. Many people using this medication do not have serious side effects. Sexual activity may put extra strain on your heart, especially if you have heart problems. If you have heart problems and experience any of these serious side effects while having sex, stop and get medical help right away: severe dizziness, fainting, chest/jaw/left arm pain, nausea. Rarely, sudden decreased vision in one or both eyes (NAION) may occur. This effect may or may not be caused by sildenafil. If this serious problem occurs, stop taking sildenafil and get medical help right away. You have a slightly greater chance of developing NAION if you have heart disease, diabetes, high cholesterol, certain other eye problems (“crowded disk”), high blood pressure, if you are over 50, or if you smoke. Rarely, a sudden decrease or loss of hearing, sometimes with ringing in the ears and dizziness, may occur. Stop taking sildenafil and get medical help right away if these effects occur. In the rare event you have a painful or prolonged erection lasting 4 or more hours, stop using this drug and get medical help right away, or permanent problems could occur. A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing. This is not a complete list of possible side effects.
Sildenafil increases the effects of blood pressure lowering medications. It also increases the blood pressure lowering effects of nitrates, for example, isosorbide dinitrate (Isordil), isosorbide mononitrate (Imdur, Ismo, Monoket), nitroglycerin (Nitro-Dur, Transderm-Nitro) that are used primarily for treating angina. Patients taking nitrates should not receive Sildenafil.