The drugs which are known as anorectics suppress the appetite and suppress hunger pangs.

According to the International Narcotics Control Board (INCB), the UN's drugs watchdog, anorectics are being used indiscriminately to feed society's obsession with being slim despite possible fatal consequences.

The INCB says although measures introduced by some countries such as Denmark, France and Chile had helped reduce the use of diet drugs, in countries such as Argentina, Australia, Brazil, the Republic of Korea and Singapore, the consumption of anorectics has risen significantly.

Anorectics are often prescribed by doctors for people who are obese and trying to lose weight and also for the treatment of narcolepsy and attention deficit disorder.

The INCB says stricter control measures are needed on the part of governments and health authorities to monitor the distribution of diet drugs and whether they are being over-prescribed.

The INCB says anorectics can be addictive and they stimulate the central nervous system, therefore indiscriminate use could produce serious adverse effects.

It seems an overdose of anorectics is potentially very dangerous and may lead to panic attacks, aggressive and violent behaviour, hallucination, respiratory depression, convulsions, coma and death.

This is why the drugs have to be prescribed by a doctor who has carefully assessed the risks as against the benefit for the patient.

The report found the highest consumption of anorectics was in the Americas, particularly in Brazil, where many of the world's diet drugs are made.

The INCB also found the abuse of prescription drugs is about to exceed the use of illicit street narcotics worldwide, and is creating a deadly new trade in counterfeit painkillers, sedatives and other medicines with the power to kill.

Prescription drug abuse already has outstripped traditional illegal drugs such as heroin, cocaine and ecstasy in parts of Europe, Africa and South Asia.

In the United States alone, the abuse of painkillers, stimulants, tranquilizers and other prescription medications has gone beyond "practically all illicit drugs with the exception of cannabis," with users increasingly turning to them first, the INCB says.

Unregulated markets in many countries make it easy for traffickers to peddle a wide variety of counterfeit drugs using courier services, the mail and the Internet.

Narcotics Control Board President Philip O. Emafo says gains in past years in international drug control could be seriously undermined by this development.

Emafo says discount medications that appear to be authentic often turn out to be powerful concoctions devised from recipes posted on the Web and instead of healing, they can kill.

The World Health Organization estimates that up to 50 percent of all drugs taken in developing countries are believed to be counterfeit.

Buprenorphine, an analgesic, is apparently the main injection drug in most of India, and it is also trafficked and abused in tablet form in France, where the INCB estimates 20-25 percent of the drug sold commercially as Subutex is being diverted to the black market.

The number of Americans abusing prescription drugs nearly doubled from 7.8 million in 1992 to 15.1 million in 2003, and among their prescription drugs of choice are the painkillers oxycodone, sold under the trade name OxyContin, and hydrocodone, sold as Vicodin and used by 7.4 percent of college students in 2005.

The number of U.S. high school and college students abusing illicit drugs declined in 2006 for a fourth consecutive year, but the INCB says the high and increasing level of abuse of prescription drugs by both adolescents and adults is a serious cause for concern.

What is more counterfeiters are exploiting the intense demand for prescription drugs that can give a "high" comparable to cocaine, heroin or methamphetamine.

In Scandinavia the demand for flunitrazepam, a sedative sold as Rohypnol and widely known as a date rape drug, is increasingly being met by unauthorized production.

In North America, where widespread abuse of prescription drugs, including the narcotic fentanyl, which is 80 times as potent as heroin, has been blamed for a rise in related deaths.

Emafo says the very high potency of some of the synthetic narcotic drugs available as prescription drugs presents, in fact, a higher overdose risk than the abuse of illicit drugs.

Emafo says nations should pay closer attention and share data on counterfeit drug seizures.

Other findings in the annual report include the record high cultivation of opium poppy in Afghanistan, Iran's emergence as the world's No. 1 abuser of opiates, and the boards opposition to so-called "safe injection rooms," where addicts are given clean needles.

Emafo says this cannot be treatment and is not healthy.