Patients and health professionals need more training about the potential risks of over-the-counter (OTC) medicines, which are being taken in increasing quantities, British doctors said on Tuesday.

Britain leads the world in expanding the range and availability of OTC medicines, as part of a government drive to encourage people to take more responsibility for their own health.

But the British Medical Association (BMA) said greater use of such drugs, which are sold without a medical consultation, must be accompanied by education programmes to make people aware of the potential risks.

“It is extremely important that the public realise that just because medicines are available over-the-counter does not mean that they are risk-free,” said Dr Vivienne Nathanson, the BMA’s head of science and ethics.

Self-medication is already a lucrative business, with the British OTC drug market growing by a healthy 4.1 percent to 1.97 billion pounds ($3.55 billion) in 2003, the last year for which figures are available.

And the market is likely to continue to expand rapidly as more medicines are switched from prescription-only to OTC use, industry analysts believe.

Last year, Britain became the first country in the world to allow the sale of a cholesterol-lowering drug - a low-dose version of Merck & Co Inc’s Zocor - without prescription.

Other future switches could include treatments for several long-term conditions such as high blood pressure and Asthma.

In an outline paper two years ago, the government stated its commitment to making more medicines available without prescription and set a target of 10 such switches a year.

The commercial lure of the OTC business is expected to be reflected in keen bidding for Boots Group Plc’s Boots Healthcare International business when it is put up for sale next month.

Nathanson said it was important for doctors to know if their patients were regularly taking any OTC drugs, since there could be adverse interactions with prescription medicines.

The herbal drug, St John’s Wort, for example, interacts badly with blood thinning medicines like warfarin, the contraceptive pill and certain antidepressants.

A small percentage of patients also become dependent on painkillers after over-using OTC drugs, and there is some evidence that misuse is sometimes a problem with antihistamines, opiates, mild stimulants and laxatives, the BMA said.