UNIVERSITY students are being warned to stay away from "smart drugs" as a way of boosting their marks and staying awake.

The drugs include prescription-only medicine modafinil, which keeps people with narcolepsy alert and interested in tasks, and Ritalin, an addictive stimulant for hyperactivity disorder.

The medicines are being sold on the internet and the Medicines and Healthcare products Regulatory Agency (MHRA) has warned they can have side-effects such as heart problems, while many are fakes.

Research among more than 1,000 young people aged 18 to 30 found nine out of 10 were not worried about fake medicines and a fifth thought buying online was the same as buying in a pharmacy.

Some 14 per cent said they were also likely to buy smart drugs within the next year.

The MHRA said other side effects of such "cognitive enhancers" include the risk of dependence and psychosis.

It has seized more than 31,000 doses of narcolepsy medicines as part of a crackdown on the sale of fake and illegal drugs.

Almost 5,000 websites selling fake or unlicensed medicines have also been shut down since the start of this year.

MHRA senior policy manager Lynda Scammell said: "You may be offered smart drugs or cognitive enhancers at university. Some of them may be potent medicines which should only be prescribed by a doctor.

"Modafinil is licensed for specific medical conditions - not for use as a boost during exams. Don't put your health at risk by self-medication. It could have serious side effects.

"It's a criminal offence to supply prescription-only medicines without a valid prescription and websites offering them are acting illegally.

"Be smart - don't put your health at risk by buying medicines online and don't give your student loan to a criminal."