Viagra has been known to achieve a success rate as high as 90%. Viagra works by allowing the blood vessels in the penis to relax, which then allows more blood into these vessels resulting in increased pressure. Viagra also allows the blood pressure to be maintained in the penis which results in the body’s ability to sustain an erection and enjoy a healthy sex life. As with all medications, there is the possibility of side effects, although with Viagra the side effects tend to be mild. Side effects associated with Viagra usage may include vision abnormalities (light sensitivity or a difference in how the colors blue and green are perceived), acid indigestion, facial flushing and headaches. If you have any questions you should consult a physician or healthcare professional before taking Viagra. Men taking any nitrate-based medications, such as heart and angina prescriptions should not take Viagra. Viagra is taken orally approximately 30 – 60 minutes before engaging in sexual intercourse....