Abuse of prescribed slimming drug seen in HK

By Tan Ee Lyn

HONG KONG, June 1 (Reuters) - Doctors in Hong Kong have been prescribing a slimming drug indiscriminately to women desperate to lose weight, a group of pharmacists said on Friday, warning of an increased risk of stroke if the practice is not stopped.

The drug phentermine, an appetite suppressant that acts on the central nervous system, has a chemical structure similar to that of the stimulant amphetamine and causes side effects including high blood pressure, palpitations and insomnia.

Pharmacists in Hong Kong say some family doctors have been loosely prescribing phentermine since 2004, even to women who obviously do not need to lose weight.

Phentermine is prescribed three times more than a close alternative, sibutramine, which is patented and costlier, but which is considered safer and has fewer side effects, according to the Society of Hospital Pharmacists of Hong Kong.

"We found out that family doctors are prescribing phentermine irrationally. It's moving in the direction of abuse," said William Chui, education director at the society.

The society said between six and 10 thousand people on average were using phentermine each day.

To fight the side effects of phentermine, some doctors prescribe other drugs to lower blood pressure and heart rate, and help patients sleep.

"Many doctors prescribe phentermine and then long-acting sleeping pills to fix the symptoms. Such sleeping pills can result in dependency. That's unethical, especially when patients know nothing about drugs," Chui said.

"They also prescribe anti-hypertensive drugs to lower blood pressure which has been raised by the phentermine."

Chui warned of dire consequences.

"Phentermine affects blood pressure and heart rate. If you have potential cardiovascular disease, it will worsen your condition. It can worsen your arrhythmia, and if your blood pressure increases, you can suffer from a stroke," he said.

Sibutramine is known by its brand, Reductil. Phentermine is off-patent and costs a fraction of the patented sibutramine.

Phentermine was part of a weight loss drug combo known as "fen-phen" (fenfluramine and phentermine) which was wildly popular during a diet craze in the United States in the 1990s.

But the Food and Drug Administration banned fenfluramine, and a related drug, dexfenfluramine, in 1997 after studies linked them to heart valve damage. Fenfluramine and dexfenfluramine were made by Wyeth WYE.N, which continues to be hounded by liability claims. Phentermine remains on the market.

The slimming craze has taken Asia by storm over the last decade. Classifed as health products, many brands of diet pills and teas -- some containing controlled substances -- are readily available in supermarkets in the region and on the Internet.

IT'S ALL ABOUT BUSINESS

Chui said doctors prescribe more phentermine because it's cheaper and gives faster results.

"GPs don't prescribe sibutramine because phentermine's response is very quick. You can reduce up to 6 kg in 2-3 weeks. But Reductil cuts 2-4 kg in 1-2 months. That's a huge difference. When you have quick fixes, you attract business," he said.

"It's very obvious that doctors just want to make money." The U.S. FDA approves phentermine only for people who are obese, or with a Body Mass Index (BMI) of 30 and over. It must also be accompanied by exercise and proper diet control.

But some doctors in Hong Kong disregard these guidelines, Chui said. Some double the recommended dose of 15 milligrammes to quicken results, he said, contending that doctors rarely warned patients that they would recover the pounds they lost once they went off the controlled drug. This practice came to light in 2004 when patients turned up in government hospitals complaining of various side effects.

Henry Yeung, president of the Hong Kong Doctors' Union, said doctors had to check patients' BMI, state of health and inform them of side effects of drugs before making a prescription.

"If management of a patient is inappropriate or falls short of standards, the medical council will look into it ... but patients need to be sensible. They shouldn't force doctors to go into grey areas (by demanding certain drugs)," Yeung said.