Viagra.

Viagra (sildenafil) is an anti-impotence medicine that has been used for many years to treat male impotence, or erectile dysfunction. The effects of this medicine are based on interfering with an enzyme in your body known as PDE5 and preventing the blood from escaping back into the body too soon. Viagra is supposed to be taken about 30-60 minutes before having sex. Some time is required for Viagra to become efficient. From that point on you can expect up to 4 hours of efficiency. You will need to talk to your doctor about your personal risks. For instance, the following are risk factors for developing sudden vision loss – a serious but quite rare condition associated with taking Viagra: high cholesterol, high blood pressure, pre-existing eye problems, heart disease, smoking, being over 50 years old, and diabetes. Viagra is tolerated very well – and in most cases the patients get just a few mild side effects that are most likely to go away on their own. The following mild side effects are possible: light sensitivity, heartburn, nosebleeds, changes in color vision, muscle aches, flushing, headache, insomnia, diarrhea, numbness, burning, or tingling.