Viagra is a medication for erectile dysfunction. It works by relaxing your blood vessels and increasing the blood flow to your penis. According to a recent study, two out of three men who experienced erectile problems reported that taking a PDE-5 inhibitor such as Viagra improved their erection. In most cases, Viagra takes effect within 30 minutes.
What is the most important information I should know about oral Viagra ?
Do not take sildenafil if you are also using a nitrate drug for chest pain or heart problems. This includes nitroglycerin (Nitrostat, Nitrolingual, Nitro-Dur, Nitro-Bid, and others), isosorbide dinitrate (Dilatrate-SR, Isordil, Sorbitrate), and isosorbide mononitrate (Imdur, ISMO, Monoket). Nitrates are also found in some recreational drugs such as amyl nitrate or nitrite ("poppers"). Taking sildenafil with a nitrate medicine can cause a sudden and serious decrease in blood pressure.
How quickly does it work?
On average, Viagra becomes effective in just under an hour when you take a tablet on an empty stomach. Viagra can remain effective for between four and six hours. If you take it after a meal that has a high fat content, it may take longer than an hour to become effective.
Use with caution in:
- Decreased kidney function
- Decreased liver function
- Disease involving the heart and blood vessels (cardiovascular disease)
- People with any obstruction of blood flow out of the heart, eg due to narrowing of the aorta (aortic stenosis)
- Bleeding disorders, eg haemophilia
- People with an active peptic ulcer
- Conditions such as sickle cell disease, bone cancer or leukaemia in which there is an increased risk of prolonged erections (priapism)
- Men with a physical abnormality of the penis, such as severe curvature, scarring or Peyronie's disease
- Elderly people.
