What is viagra?
This was the first oral medication used in the treatment of erectile dysfunction. Remember it treats the dysfunction, but does not cure the possible underlying physical causes.

What is erectile dysfunction?
This is where men fail to respond to sexual stimulation with an erection or, having produced an erection, then fail to maintain it for more than a few minutes.

How does viagra work?
If your body is reasonably fit and healthy, you should be able to respond to sexual stimulation with an erection. One of the most common reasons for failure is that, by mistake, your body releases a chemical message to cancel the erection. This chemical is called phosphodiesterase type 5 (PDE5). Viagra prevents it from taking effect. It is a PDE5 inhibitor.

How long does it take viagra to work?
This depends on how big the dose and whether you have recently eaten. If you take a larger dose on an empty stomach, it will take effect in between 15 and 30 minutes. But if you take a small or the standard dose on a full stomach, particularly if the meal had a high fat content, it can be more than an hour before you will feel any effects.

How long do the effects last?
Again it varies with the size of the dose and your physical size but, in general, the effects last between 4 and 6 hours.

How often can you take viagra?
You should only take it once in any 24 hour period.

Can you drink alcohol?
There is no problem if you are a social drinker and have one or two drinks, but you are likely to experience adverse side effects if you drink more than five units of alcohol or are an alcoholic with a continuous level of alcohol in your blood stream.

Are there any combinations of drugs to avoid?
There is always a risk when you take two or more drugs at the same time. Your doctor will be able to advise on the full range of drugs and the dosages to adopt. The most danger comes when you mix viagra with any drug that lowers your blood pressure, e.g. any drug containing a nitrate, alphablockers, etc.

Can everyone take viagra?
People with some diseases or disorders either should not take viagra or only take it at a reduced dose. Your physician will advise on the detail but the most common problems come if you have cardiovascular disease or a disease of the liver or kidney.

What are the most common side effects?
A small number of men experience a headache, feel their stomach upset, or experience blushing. These are usually relatively minor and pass quite quickly. If you have different problems or these problems grow more serious, get medical advice.