Viagra FAQs

working mechanism of viagra

Does viagra Work for everyone?
Individual results vary but viagra was shown to be effective in men with severe erectile dysfunction for up to 4 hours.

How does viagra work?
viagra increases blood flow to the penis, allowing more blood flow into the penis as occurs naturally, when a man is sexually stimulated. With more blood flowing in and less flowing out, the arteries in the penis enlarge resulting in an erection. If this mechanism is not working properly, a man has difficulties in having and keeping an erection. Using viagra a man can respond to sexual stimulation, during a sexual encounter and once it is over the erection goes away.

Will viagra work immediately?
It takes 60 minutes before viagra starts to work and remains working for up to 4 hours.

Does viagra automatically cause an erection?
No. With viagra, you must be sexually aroused to get an erection. If you take viagra and are not sexually stimulated, nothing will happen–you won't get an erection just by taking the pill. viagra is not a hormone. It is not an aphrodisiac. It is a prescription medication, that can improve the erectile function of most men with erection problems.

How much viagra can I take?
viagra comes in different doses (25 mg, 50 mg, and 100 mg). Like many medications, your healthcare provider may have to adjust your initial viagra dose if it doesn't produce the desired results, or you are bothered by side effects. Do not take more viagra than your healthcare provider prescribes. viagra can be used only once a day.
If you are older than 65 years, have a serious liver or kidney problem, or are taking protease inhibitors, such as for the treatment of HIV, your healthcare provider may start you at the lowest (25-mg) dose of viagra.

How often can I take viagra?
For most patients, viagra should be taken once a day as needed. In patients taking certain protease inhibitors (such as for the treatment of HIV), it is recommended to not exceed a maximum single dose of 25 mg of viagra in a 48-hour period.

Who should not take viagra?
viagra is not for newborns, children, or women. Do not let anyone else take your viagra. viagra must be used only under a healthcare provider's supervision.

Before you start any treatment with viagra, be sure to ask your healthcare provider if your heart is healthy enough. If you are a man who uses nitrate drugs, like nitroglycerine, never take viagra. The combination of viagra and nitrates can make your blood pressure suddenly drop to unsafe levels. You could get dizzy, faint, or even have a heart attack or stroke. Nitrates are found in many prescription medications that are used to treat angina (chest pain due to heart disease) such as:

Nitroglycerin (sprays, ointments, skin patches or pastes, and tablets that are swallowed or dissolved in the mouth) Isosorbide mononitrate and isosorbide dinitrate (tablets that are swallowed, chewed, or dissolved in the mouth) Nitrates are also found in recreational drugs such as amyl nitrate or nitrite ("poppers"). If you are not sure if any of your medications contain nitrates, or if you do not understand what nitrates are, ask your healthcare provider or pharmacist.

What if viagra doesn't work?
While viagra is effective in up to 4 of 5 men, it's not effective for everyone. If it doesn't work for you, contact your healthcare provider to discuss other treatment options.

Can I take viagra with alcohol?
Drinking alcohol can temporarily impair the ability to get an erection. To get the maximum benefit from your medication, you are advised not to drink large amounts of alcohol before taking viagra.

Can I take viagra after eating?
Yes, but taking viagra after a high-fat meal (such as a cheeseburger and French Fries) may cause the medication to take a little longer to start working.

What are the side effects of viagra?
Like all medications, viagra can cause some side effects. These are usually mild and don't last longer than a few hours. Some of these side effects are more likely to occur with higher doses of viagra. With viagra, the most common side effects are headache, facial flushing, and upset stomach. viagra may also briefly cause bluish or blurred vision or sensitivity to light. In the rare event of an erection lasting more than 4 hours, seek immediate medical help

Information is provided by Pfizer