Although slimming products containing the amphetamine are banned in the UK, people looking for a quick fix for weight problems are buying the products from foreign internet sites.
The latest casualty of the products was a 36-year-old man in Denmark who died from a coronary thrombosis after taking Therma Power, which contains ephedrine and caffeine.
Strong warnings have subsequently been issued from the Danish Medicines Agency.
The MHRA also highlighted a recent case of respiratory arrest in a woman from the UK after taking just three tablets of a slimming product called Grenade Fat Burner.
An MHRA spokeswoman said: 'If you have an underlying heart problem that you don't know about, (ephedrine) is going to exacerbate things.'
Middlesbrough GP Dr Bill Beeby, chairman of the GPCprescribing subcommittee, said: 'It reflects a difficulty in controlling internet sales of medication in general.'
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