Viagra (sildenafil) is a medication used to treat erectile dysfunction (ED). It is a phosphodiesterase type 5 inhibitor (PDE5 inhibitor), which means it works by increasing the amount of blood flow to the penis.

How does Viagra work?

Viagra works by relaxing the muscles in the walls of blood vessels, allowing more blood to flow into the penis. This can lead to an erection that is sufficient for sexual intercourse.

Viagra is not a cure for ED, but it can help men with ED to achieve an erection that is satisfactory for sexual intercourse. It is not known exactly how effective Viagra is, but some studies have shown that it can be effective in up to 84% of men with ED.

How is Viagra taken?

Viagra is taken orally, usually about 1 hour before sexual activity. The recommended starting dose is 50 mg, but this dose may be increased to 100 mg or decreased to 25 mg depending on the individual's response to the medication. Viagra should not be taken more than once per day.

What are the side effects of Viagra?

The most common side effects of Viagra include:

* Headache

* Flushing

* Dyspepsia

* Nasal congestion

* Diarrhea

Rare side effects of Viagra include:

* Priapism (prolonged, painful erection)

* Visual disturbances

* Hearing loss

* Seizures

Viagra is not safe for everyone. It should not be taken by men who are taking nitrates, such as nitroglycerin or isosorbide dinitrate, or by men who have a history of heart disease, stroke, heart failure, or other serious medical conditions.

How do I get Viagra?

Viagra is a prescription medication, so you will need to see your doctor to get a prescription. Your doctor will ask you about your medical history and current medications to make sure that Viagra is safe for you to take.

Viagra is a safe and effective medication that can help men with ED to achieve an erection that is satisfactory for sexual intercourse. However, it is important to talk to your doctor before taking Viagra to make sure that it is right for you.