What is Viagra's success rate?
According to an AP article released 10/27/97, Viagra achieved a success rate of 80%.

What if Viagra doesn't work for me?
If Viagra doesn't give you the results and duration you want, you might consider consulting with a urologist about some of the other popular treatments for male erectile dysfunction.

Is Viagra sold over the counter, or does it require a prescription?
Viagra requires a prescription from a doctor. It will not be sold over-the-counter.

How To Take Viagra®
Take Viagra® about one hour before you plan to have sex. Beginning in about 30 minutes and for up to 4 hours, Viagra® can help you get an erection if you are sexually excited. If you take Viagra® after a high-fat meal (such as a cheeseburger and french fries), the medicine may take a little longer to start working. Viagra® can help you get an erection when you are sexually excited. You will not get an erection just by taking the pill.

How Sex Affects the Body
When a man is sexually excited, the penis rapidly fills with more blood than usual. The penis then expands and hardens. This is called an erection. After the man is done having sex, this extra blood flows out of the penis back into the body. The erection goes away. If an erection lasts for a long time (more than 6 hours), it can permanently damage your penis. You should call a doctor immediately if you ever have a prolonged erection that lasts more than 4 hours. Some conditions and medicines interfere with this natural erection process. The penis cannot fill with enough blood. The man cannot have an erection. This is called erectile dysfunction if it becomes a frequent problem. During sex, your heart works harder. Therefore sexual activity may not be advisable for people who have heart problems. Before you start any treatment for erectile dysfunction, ask your doctor if your heart is healthy enough to handle the extra strain of having sex. If you have chest pains, dizziness or nausea during sex, stop having sex and immediately tell your doctor you have had this problem.

How Viagra® Works
Viagra® enables many men with erectile dysfunction to respond to sexual stimulation. When a man is sexually excited, Viagra® helps the penis fill with enough blood to cause an erection. After sex is over, the erection goes away.

Viagra® Is Not for Everyone
As noted above, ask your doctor if your heart is healthy enough for sexual activity. If you take any medicines that contain nitrates - either regularly or as needed - you should never take Viagra®. If you take Viagra® with any nitrate medicine or recreational drug containing nitrates, your blood pressure could suddenly drop to an unsafe level. You could get dizzy, faint, or even have a heart attack or stroke. Nitrates are found in many prescription medicines 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 medicines contain nitrates, or if you do not understand what nitrates are, ask your doctor or pharmacist. Viagra® is only for patients with erectile dysfunction. Viagra® is not for newborns, children, or women. Do not let anyone else take your Viagra®. Viagra® must be used only under a doctor's supervision.

What Viagra® Does Not Do
Viagra® does not cure erectile dysfunction. It is a treatment for erectile dysfunction. Viagra® does not protect you or your partner from getting sexually transmitted diseases, including HIV-the virus that causes AIDS. Viagra® is not a hormone or an aphrodisiac.

What To Tell Your Doctor Before You Begin Viagra®
Only your doctor can decide if Viagra® is right for you. Viagra® can cause mild, temporary lowering of your blood pressure. You will need to have a thorough medical exam to diagnose your erectile dysfunction and to find out if you can safely take Viagra® alone or with your other medicines. Your doctor should determine if your heart is healthy enough to handle the extra strain of having sex. Be sure to tell your doctor if you: have ever had any heart problems (e.g., angina, chest pain, heart failure, irregular heart beats, or heart attack) have ever had a stroke have low or high blood pressure have a rare inherited eye disease called retinitis pigmentosa have ever had any kidney problems have ever had any liver problems have ever had any blood problems, including sickle cell anemia or leukemia are allergic to sildenafil or any of the other ingredients of Viagra® tablets have a deformed penis, Peyronie's disease, or ever had an erection that lasted more than 4 hours have stomach ulcers or any types of bleeding problems are taking any other medicines

Possible Side Effects
Like all medicines, Viagra® can cause some side effects. These effects are usually mild to moderate and usually don't last longer than a few hours. Some of these side effects are more likely to occur with higher doses. The most common side effects of Viagra® are headache, flushing of the face, and upset stomach. Less common side effects that may occur are temporary changes in color vision (such as trouble telling the difference between blue and green objects or having a blue color tinge to them), eyes being more sensitive to light, or blurred vision.

Viagra® and Other Medicines
Some medicines can change the way Viagra® works. Tell your doctor about any medicines you are taking. Do not start or stop taking any medicines before checking with your doctor or pharmacist. This includes prescription and nonprescription medicines or remedies. Remember, Viagra® should never be used with medicines that contain nitrates If you are taking a protease inhibitor, your dose may be adjusted (please see paragraph below) Viagra® should not be used with any other medical treatments that cause erections. These treatments include pills, medicines that are injected or inserted into the penis, implants or vacuum pumps.

Finding the Right Dose for You
Viagra® comes in different doses (25 mg, 50 mg and 100 mg). If you do not get the results you expect, talk with your doctor. You and your doctor can determine the dose that works best for you.

Do not take more Viagra® than your doctor prescribes.
If you think you need a larger dose of Viagra®, check with your doctor. Viagra® should not be taken more than once a day. If you are older than age 65, or have serious liver or kidney problems, your doctor may start you at the lowest dose (25 mg) of Viagra®. If you are taking protease inhibitors, such as for the treatment of HIV, your doctor may recommend a 25 mg dose and may limit you to a maximum single dose of 25mg of Viagra® in a 48 hour period.