Side effects - Mephedrone fatigue: heart & breathing problems

[Synesthesiac]

swim and his friends were all quite knackered the day after doing mephedrone, and swim was wondering if anyone else has had this experience. One of swims friends in particular that got a bit carried away with the stuff (did more than 3g over three days) had to sit down and rest whenever he moved about to get his breath back and slow his heart down the day after his binge. He's says he feels back to normal now after three days or so, and he seems fine now to swim. Swim did notice some less pronounced similar effects using about 1g in total over the weekend, and so did his mates.

Even though you dont seem to get a bad comedown on the day and the first few times you use it, swim feels its not something to use more than once weekly. The side effects, very subtle though they may be at first, seem to cumulate with use if you dont leave a gap inbetween use. Though swims aware that some people do make a habit of using it frequently and report no ill effects, but no-one knows the effects in the long term.

Anyone else get this? and any ideas what may cause it?