University students hitting the books for final exams in Calgary are popping prescription stimulants that carry the risk of side-effects,doctors warn.

Dextroamphetamine, sold as Dexedrine, or "dex," is prescribed to treat narcolepsy, or sudden sleep attacks, and for people with attention deficit hyperactivity disorder, to help them focus and concentrate better. For those who do not have ADHD, the drug works like a stimulant.

'I take it before an exam so I'm extra focused.' —University of Calgary first-year business student

"I think it is a time-release kind of drug, so it just slowly goes through your body," said a first-year business student at the University of Calgary, who did not want his name used because he buys Dexedrine for five dollars a pill from a friend with ADHD.

"Before you know it, well geez, I've done four hours of hard-core studying and I remember every bit of information," he said, adding he thinks the drug has helped him to achieve higher marks. "I take it before an exam so I'm extra focused."

Dexedrine should not be taken without a prescription, said Dr. Prem Chengalath, a physician in Calgary.

"It has side-effects. It has addictive properties as well," Chengalath said."Anything which gives you a high is going to give you a low, and sometimes it could be a very bad low."

Taking Dexedrine without a prescription may also lead to disrupted sleep patterns, loss of appetite and elevated heart rate, said Debbie Breckner, director of the university's Wellness Centre. It's not recommended for coping with stress or dealing with exams, Breckner said.

It is not known how many students are using Dexedrine to study. Robin Tribble said its use is widespread among her friends in first year who live in residence. Some of the people are now dependent on Dexedrine for studying, shesaid.

"I don't see the point," Tribble said. "What are you going to do the rest of your life whenever you have something big coming up? You can't just keep taking Dexedrine your entire life."

Officials at the Wellness Centre are not overly concerned, saying their doctorshave not seen an increase in discussions with students who may be using Dexedrine.

As a street drug, higher doses ofthe methamphetamine are smoked or injected.