Viagra (sildenafil citrate) is a prescription medicine recommended for patients suffering from erectile dysfunction and unable to lead a normal sex life without this kind of assistance. Viagra is available in three different dosages and it’s very important to find the dose that will be minimal and allow getting stable erections without affecting your health or wellbeing. Viagra can be dangerous if combined with isosorbide mononitrate, nitrates or isosorbide dinitrate, as it can lead to potentially fatal health effects. Make sure you let your doctor know if you have or used to have any of the following medical conditions: chest pain, high cholesterol, high or low blood pressure, stomach ulcer, pulmonary veno-occlusive disease, blood cell problems, diabetes, liver disease, blood circulation problems, irregular heartbeat, heart disease, conditions affecting the shape of the penis, bleeding disorder, kidney disease, heart attack, or a stroke. Your doctor may need to monitor you through the treatment to make sure Viagra is efficient and safe for you. Mild side effects are normal and may include stuffy nose, warmth or redness in your face, neck, upset stomach, headache, memory problems, and back pain.