Viagra rivals add hours of hope for men

Barbers' offers of 'something for the weekend' are about to face pharmaceutical competition. Drug manufacturers are set to launch sexual pick-me-ups that will last from Friday night to Sunday morning.

The weekend sex drugs - to be launched next year - will have the same impact as Viagra, but will have effects that will last for days, not hours.

Barbers' offers of 'something for the weekend' are about to face pharmaceutical competition. Drug manufacturers are set to launch sexual pick-me-ups that will last from Friday night to Sunday morning.

The weekend sex drugs - to be launched next year - will have the same impact as Viagra, but will have effects that will last for days, not hours.

After five years in which Pfizer's drug has been taken by more than 20 million males, achieving annual sales of Ј1 billion, the US drug manufacturer now has a battle on its hands.

'Viagra was a breakthrough,' said Peter Baker of the medical campaigning group Men's Health Forum. 'It revitalised the lives of millions of men suffering from impotence. Now it has competition, which is good.'

Pfizer executives have reacted calmly to the imminent arrival of Cialis, to be launched by Eli Lilly and the Icos Corporation, and of Levitra, a joint venture between Bayer and GlaxoSmithKline. 'There is plenty of room for competition,' said Geoff Cook, a senior executive.

Cialis and Levitra are to be launched early next year, having passed safety tests, and survived an unsuccessful bid by Pfizer to block their sale on the grounds of an alleged patent infringement.

Crucially, both sets of manufacturers claim their products have longer-lasting effects than Viagra. And that, say experts, should help take the stopwatch out of the sex lives of those on current therapies, and put spontaneity back into their relationships.

As Professor Roger Kirby, of St George's Hospital, London, put it: 'If you only have a few hours of effectiveness, timing can become very tricky. If you have something that lasts days, you have the whole weekend to work on.'

Pfizer remains unworried, however. 'A drug that is active for days, not hours, has more chance to trigger side-effects,' warned Cook. 'Viagra is still the one, tried-and-tested drug for men.'

More importantly, the arrival of two new anti-impotence drugs will bring diversity to an annual market that will reach Ј5bn in a few years. More than 150 million men, including two million in Britain, suffer from erectile dysfunction, it is estimated. 'We get 1,000 calls a month to our helpline,' said Ann Taylor of Impotence Research.

Viagra was developed after Pfizer scientists discovered, during trials on potential angina drugs, that its active ingredient, sildenafil, produced dramatic improvements in sexual functioning.

'It also gave men confidence,' said Taylor. 'They could go to doctors for the first time and know there might be help for them.'

Impotence - apart from triggering depression, the break-up of relationships, and occasionally suicides - also indicates a man may be suffering from more profound illnesses, in particular heart diseases and diabetes. 'The more men go to doctors to discuss these problems, the more of these serious conditions will be picked up,' added Baker. 'That has been the real benefit of Viagra.'