Age greater than 50 years or Coronary artery disease or Crowded disc or low cup to disc ratio in the eye an eye disorder or Diabetes or Hyperlipidemia high fats in the blood or Hypertension high blood pressure or Non-arteritic anterior ischemic optic neuropathy or NAION serious eye condition , history of or Smoking—May increase the chance for a serious side effect in the eye called NAION. Do not press on the plunger of the syringe. These small differences affect the way each medication works, such as how quickly it takes effect and wears off, and the possible side effects. Treatment can be more successful for you when you involve your partner. Sildenafil Viagra. The dosages might also be unknown, or they might have been contaminated during formulation.Viagra is a drug that helps treat erectile dysfunction. It improves blood flow to the penis, and its effects can last for up to 4 hours, although the effect will likely be stronger after 2 hours. Sildenafil is a medicine used to treat erection problems (erectile dysfunction). Sildenafil is also sometimes used to treat pulmonary hypertension (high blood pressure in the blood vessels that supply the lungs).  · By controlling the enzyme, sildenafil helps to maintain an erection after the penis is stroked. 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 men and women to treat the symptoms of pulmonary arterial hypertension.