Launched by Pfizer in 1998, Viagra, the trade name for sildenafil citrate, is a prescription drug used to help men with erection difficulties (known as impotence, or erectile dysfunction). Taken in pill form, it works by promoting the flow of blood to the penis during arousal. It is not an aphrodisiac. It won't just give you wood; you need to be turned on for the drug to be effective.  

What are the effects of taking Viagra?

• Simple alternative to other impotence treatments (such as injections, vacuum flasks and penile implants - which can be off-putting for obvious reasons)
• Helps impotent males achieve harder erections for longer durations
• Taken as a single pill, with effects kicking in 30 minutes later
• Enables user to get hard any time for up to four hours (with sexual stimulation).

What are the risks of taking Viagra?

• Some users report temporary side effects, ranging from headaches to flushed skin, stomach upsets, blurred vision and muscle ache. See your GP if problems persist
• Viagra relaxes the muscles in blood vessels, thus increasing blood flow potential. This means it isn't recommended for impotence sufferers with cardiovascular problems
• Combining drugs is always dangerous. Using Viagra with other nitrate drugs such as poppers is especially risky as it can lower blood pressure to dangerous levels.

The law and Viagra:

• Viagra can only be obtained legally in the UK by prescription from your GP, except in a few rare circumstances where pharmacies have obtained the right to sell it.
• The drug is widely available on the internet. Drugs sold online could be out of date or fake - only take prescription drugs without supervision from a medical practitioner.
• UK law prohibits possession of Viagra for the purposes of selling it.

Other terms for Viagra:

Blue, bluey, Mr Blue.

Similar prescription drugs:

Viagra is the first - and most well-known - impotence treatment in pill form, but other brands are emerging on the market such as Cialis and Levitra.

If you're planning to take this drug:

Be aware that physical impotence tends to affect older males. Men in their teens or twenties who can't get it up may find the cause is psychological, such as stress or performance anxiety. This means if there's no physical problem, Viagra won't make a difference.

Some recreational drugs are known to have erection-killing properties, such as cocaine and speed, while ecstasy users may feel loved up but unable to perform. It is not advisable to take Viagra to counter such effects as the drugs may have a conflicting impact on body-temperature control, heart rate and blood pressure.

Updated: 05/10/2010