Dr John Chisholm is worried that the campaign will stimulate excessive demand

They are worried it will stimulate demand for expensive branded products at a time when the government is pressurising doctors to prescribe cheaper generic alternatives.

In the US, where prescription drugs can be freely advertised, the pharmaceutical market is expanding at 12% a year, compared to just 5% a year in Europe.

Dr John Chisholm, chairman of the British Medical Association's GP Committee, said he welcomed the incontinence campaign which he said would raise awareness about a subject which caused much embarrassment.

But he warned the campaign must not be seen as the first step towards direct advertising of prescription drugs.

He said: "In an under-resourced health service there is only so much money to go round, and, if some of the pharmaceutical companies are actually stimulating a demand in particular areas, that can inhibit the ability of the service to deliver the care that patients need in other areas."

Patients group supports campaign

Claire Rayner dismissed doctors' concerns

However, Claire Rayner, president of the Patient's Association, said: "As long as you can make it clear at all times that you are not linking a named drug or a named prescription with the information that you are giving I cannot see there is a problem.

"The fact that this campaign has in tiny letters at the bottom 'sponsored by Pharmacia & Upjohn' - what difference does it make if it does the job?

"The job is to help people who have a very real symptom that they often feel they cannot possibly talk to the doctor about.

They think they are unique. They don't think other people have the problem, and it's very comforting to know that it is common and treatable."

Roy Sutherwood, director of public affairs for Pharmacia & Upjohn, said the company had consulted widely with health professionals and interested groups before launching their campaign.

He said: "This is not advertising, this is a health educational campaign aimed at encouraging patients to seek the help that they need."

Mr Sutherwood said research showed that 23% of people over the age of 40 suffered from urinary incontinence, but up to 50% of suffers never sought medical help for a condition that could be easily treated.