It belongs to a class of drugs called phosphodiesterase type 5 (PDE5) inhibitors. (A class of drugs is a group of medications that act in a similar way.) Viagra works by increasing blood flow to your penis, which helps you have and keep an erection. But this drug only works if you're sexually aroused.

Viagra contains the active ingredient sildenafil, a PDE5 inhibitor that improves blood flow to your penis and makes it easier to get and maintain an erection. How safe is Viagra? For most men, Viagra is a safe and effective medication.

Viagra helps to improve blood flow to the penis, but your brain is still your most valuable sex organ. Viagra will not work if you're not in the mood. Some potential side effects of Viagra are headache, runny or blocked nose, or a nosebleed. Some men feel lightheaded or dizzy.

Viagra can help you have an erection when sexual stimulation occurs. An erection will not occur just by taking a pill. Follow your doctor's instructions. During sexual activity, if you become dizzy or nauseated, or have pain, numbness, or tingling in your chest, arms, neck, or jaw, stop and call your doctor right away.

Viagra is a drug that helps treat erectile dysfunction. It improves blood flow to the penis, and its effects can last for up to 4 hours, although the effect will likely be stronger after 2 hours. Erectile dysfunction is a common condition that can affect males of any age.

Viagra (sildenafil) is a prescription medication used to treat erectile dysfunction. Headache, flushing, and upset stomach are common Viagra side effects. These effects are usually mild and often resolve on their own. While rare, Viagra can cause an erection that lasts longer than 4 hours (priapism).

Importantly, you shouldn't take Sildenafil or Viagra more than once a day. Taking too much of the drug can increase your chances of side effects – including dizziness and fainting, as well as painful erections that won't disappear.

Viagra is a drug that helps treat erectile dysfunction. It improves blood flow to the penis, and its effects can last for up to 4 hours, although the effect will likely be stronger after 2 hours.

On average, Viagra lasts between 2 and 3 hours before its effects start to diminish. Viagra can last up to 5 hours or longer depending on your dosage, your body's metabolism, and other external factors.

The effects of Viagra can last 4 to 8 hours, depending on the individual person and the dose you take. In fact, some people may experience more than one erection during this time. However, just because Viagra can stay in your body for up to 8 hours doesn't mean your erection should last that long.

Strictly speaking, no, Viagra does not keep you hard after ejaculation. Nevertheless, studies suggest that it could reduce your refractory period, and it will work for 4-6 hours, meaning that once your refractory period's over, you should have no trouble getting another erection.

Depending on how your body metabolizes it, you may be able to get an erection several times with Viagra in your system. Viagra probably won't make you last longer in bed, though. No research has proven definitively that Viagra can increase how long you can have sex.