1. Launched by Pfizer in 1998, the blue diamond-shaped tablets (which have the chemical name sildenafil) rapidly became the fastest-selling drug in history. Nearly 37 million tablets for erectile dysfunction (ED) have been prescribed in Britain to date.

2. Viagra will cause erection only if you are sexually aroused by your partner, hence the inexorable rise of the Viagra divorce when men who get their mojo back trade in the missus for a 25-year-old.

3. Too embarrassed to go to your GP? You can get four blue diamonds at Boots without a doctor's prescription, if you submit to a blood pressure and diabetes test. DrThom (www.drthom.com) can prescribe Viagra if you fill in a health questionnaire.

4. Viagra is a cure; ED is a symptom. Men who bypass their GP and order tablets over the internet could be ignoring underlying cardiovascular or metabolic problems. At least half the tablets sold online are counterfeit.

A magic wand for him but not for her

Men can now get Viagra prescribed online without seeing their doctor - but their partners may not be very thankful

5. Swallowing your pills with grapefruit juice may cause a modest increase in the blood level of sildenafil, the active ingredient in Viagra. Alternatively, red watermelon contains citrulline, which the body converts to arginine, a chemical that boosts nitric oxide and relaxes the blood vessels in the same way as Viagra. In Italy, scientists have discovered that icariin, a compound found in the herb horny goat weed, has the potential to compete with Viagra.

6. Unless your erectile dysfunction is related to certain medical conditions (see the list at www.netdoctor.co.uk/erectiledysfunction/prescription.htm), you can't get Viagra tablets free on the NHS. However, your GP can write you a private prescription and he won't ask to see if you can, or can't, get it up.

7. The most common side-effects associated with Viagra are headache, flushing, dizziness palpitations, indigestion and blurred or blue- tinged vision. In 2005 and 2007 the US Federal Drugs Adminsitration instructed Pfizer to advise users of the risk of blindness and deafness. Viagra can be fatal if used in combination with nitrates, the drugs prescribed to treat heart problems such as angina. For a detailed list of side effects www.rxlist.com/viagra-drug/ article.htm#ad.

8. Viagra is being linked to male infertility. Dr David Glenn, a consultant gynaecologist at Queen's University Belfast, has discovered that exposure to Viagra damages sperms' ability to penetrate and fertilise the egg.

9. Sextasy, Poke, Vitamin V - on the club circuit Viagra is taken to counterbalance drugs such as cocaine, crack and ecstasy, which inhibit erection. However, mixing “poppers” (amyl nitrate) with Viagra can lead to a drastic drop in blood pressure causing stroke, heart attack or death.

10. Will you do anything to get hold of Viagra? Do you miss work because of it? It was only a matter of time - www.viagraholics.com.

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