Abuse of prescribed slimming drug seen in HK

By Tan Ee Lyn

HONG KONG (Reuters) - Hong Kong doctors are over prescribing a slimming drug to women desperate to lose weight, pharmacists said on Friday, warning its misuse could increase the risk of stroke.

The generic 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.

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.

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 two 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 6,000 and 10,000 people on average were using phentermine, now off patent after first being approved by the FDA in 1959, in Hong Kong each day.

To fight the side-effects, 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."

SIDE -EFFECTS

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.

This practice came to light in 2004 when patients turned up in government hospitals complaining of various side-effects.

Twelve people were admitted to hospital in the past year and some of them needed emergency treatment. In one instance, a woman was found to have been prescribed both phentermine and sibutramine.