There has been a dramatic rise in the number of children on anti-obesity drugs, but most stop taking them before they have any benefit, research found today.
Since 1999, the number of under-18s on the medicines has risen 15-fold across the UK, data showed.
Researchers estimated that 1,300 young people could now be being prescribed anti-obesity drugs every year.
The drugs are only licensed for use in adults, meaning they are being prescribed off-licence by family doctors.
The study, published in the British Journal of Clinical Pharmacology, looked at the use of orlistat (Xenical), sibutramine (Reductil) and rimonabant (Acomplia) in children up to the age of 18.
It focused on prescribing data from the UK General Practice Research Database between January 1, 1999, and December 31, 2006.
Overall, 452 youngsters received 1,334 prescriptions during the study period, and the prevalence of the drugs rose 15-fold among both boys and girls during that time.
Most prescriptions were for 14-year-olds, although 25 prescriptions were written for children under the age of 12.
Orlistat accounted for 78.4% of all prescriptions and only one patient was prescribed rimonabant.
Around 45% of the youngsters stopped taking orlistat after only one month, as did 25% of those on sibutramine.
The estimated average length of treatment with orlistat was three months and four months with sibutramine.
The researchers, from University College London, said it was unclear whether this was due to side-effects, which include diarrhoea, or other reasons.
Russell Viner, one of the authors of the study, said: “It's possible that the drugs are being given inappropriately, or that they have excessive side effects that make young people discontinue their use. On the other hand, they could be expecting the drugs to deliver a miracle ‘quick fix’ and stop using them when sudden, rapid weight loss does not occur.”
Guidance from the National Institute for Health and Clinical Excellence (Nice), published in December 2006, said the drugs should only be considered for children and adults after dietary, exercise and behavioural approaches have failed.
“Drug treatment is not generally recommended for children younger than 12 years,” the guidance said.
“In children aged 12 years and older, treatment with orlistat or sibutramine is recommended only if physical comorbidities (such as orthopaedic problems or sleep apnoea) or severe psychological comorbidities are present.”
The guidance also states that prescribers should submit data on the use of these drugs in young people.
Study author Ian Wong said children who are prescribed orlistat may need more support and should be made fully aware of the potential side effects.
“You have to tell them that, yes, it is healthier not to absorb the fat, but if they continue to eat as much as they used to then it will be really unpleasant. The key thing is that the drug itself is not the answer. Kids should only be using it as part of a comprehensive weight-loss programme.”
Tam Fry, from the National Obesity Forum, said: “This rise in the use of drugs is a real indictment on society. It seems to me that we are ignoring measures to prevent our children becoming obese and then turning to drugs as a treatment of choice when they should be a last resort.”