What Is Viagra?
Viagra® (sildenafil citrate) is a prescription medication used for treating problems with obtaining or maintaining an erection. Erectile dysfunction (ED), also known asimpotence, can be a total inability to achieve an erection, an inconsistent ability to do so, or a tendency to sustain only brief erections. Essentially, erectile dysfunction is the repeated inability to get or keep an erection that is firm enough for sexual intercourse.
Viagra is manufactured by Pfizer, Inc.
The medication works by blocking a chemical that causes blood to flow out of the penis. More blood in the penis means an improved erection.
In previous clinical studies, up to 88 percent of men reported an improvement in their erections when taking Viagra. It was also shown to be effective in men with certain medical conditions and after various types of surgeries (see Effects of Viagra for more information).
When Does It Start Working?
Many men wonder how long they will have to wait for the drug to work. The waiting time varies, depending on the individual. In clinical studies, Viagra began to work in as little as 14 minutes. For most men, however, it begins working within 30 minutes. The drug can continue to work for at least four hours, but, on average, the response decreases after about two hours.
General considerations regarding when and how to take Viagra include the following:
- The medication comes in tablet form. It is taken as needed, usually one hour before sexual activity. However, you should not take it more than once a day.
- You should take your dose with a glass of water, although you can take it with or without food. If you take it with food, keep in mind that fatty meals may decrease the levels of Viagra in the blood.
- For the medication to work properly, you have to take it as prescribed. It will not work if you stop taking it.
The dose of Viagra your healthcare provider recommends will vary, depending on a number of factors, including:
- Your age
- Other medical conditions you may have
- Other medications you may be taking.
As always, do not adjust your dose unless your healthcare provider specifically instructs you to do so.
Side Effects of Viagra
As with any medicine, side effects are possible with Viagra; however, not everyone who takes the drug will experience side effects. In fact, most men tolerate it well. If side effects occur, in most cases, they are minor, meaning they require no treatment or are easily treated by you or your healthcare provider.
The most common side effects include:
- Headache --in up to 16 percent of men
- Facial flushing -- up to 10 percent
- Indigestion (dyspepsia) -- up to 7 percent
- Nasal congestion -- up to 4 percent
- Urinary tract infections (UTI) -- up to 3 percent
- Vision problems, including trouble telling the difference between blue and green, increased sensitivity to light, or blurred vision -- up to 3 percent
- Diarrhea -- up to 3 percent
- Dizziness -- up to 2 percent
- Unexplained rash -- up to 2 percent.
If you have a heart or blood vessel disease (cardiovascular disease) or significant heart disease risk factors, you will have an increased chance of developing serious problems with the heart, brain, and blood vessels. These problems can result in a heart attack, stroke, or sudden death.
In people taking Viagra or other PDE5 inhibitors, there have been rare cases of a condition called non-arteritic anterior ischemic optic neuropathy (NAION). This condition can lead to sudden loss of vision in one or both eyes. If you experience any loss of vision while taking Viagra, contact your healthcare provider immediately (see Viagra and Blindness).
Drug Interactions With Viagra
Viagra can potentially interact with several different medications (see Viagra Drug Interactions for more information).
Prior to taking the drug, tell your healthcare provider if you have:
- Heart disease
- Liver disease or liver failure, includingcirrhosis
- A history of heart attack, stroke, or life-threatening arrhythmia within the past six months
- Retinitis pigmentosa, which is a rare eye problem
- Low blood pressure (hypotension)
- High blood pressure (hypertension)
- Sickle cell anemia
- Multiple myeloma
- Leukemia
- A history of priapism, which is a painful erection lasting longer than six hours
- Any condition that causes a penis deformation, such as angulation, Peyronie's disease, or cavernosal fibrosis
- Any allergies.
Also, tell your healthcare provider about all medicines you take, including prescription and non-prescription medicines, antacids, vitamins, and herbal supplements.
Only a small number of people have overdosed on this drug. Therefore, overdose symptoms are not well known. If you happen to take too much Viagra, seek immediate medical attention.
Viagra should be stored at room temperature, away from moisture and heat. Keep it and all medications out of the reach of children.
What Strengths of Viagra Are Available?
Several strengths of tablets are available. These include:
- Viagra 25 mg
- Viagra 50 mg
- Viagra 100 mg.
Currently, there is no generic Viagra available for sale (see Generic Viagra for more information).
