The mephedrone wiki page refers to cardiotoxicity several times:
"Research very strongly suggests mephedrone's cardio-toxicity, but its neurotoxicity as well (see section on current research)."
"In "Beta-keto amphetamines: studies on the metabolism of the designer drug mephedrone and toxicological detection of mephedrone, butylone, and methylone in urine using gas chromatography–mass spectrometry", Meyer et al. confirmed that mephedrone metabolizes to 4-methyl-ephedrine, a highly cardiotoxic compound (2010, Analytical and Bioanalytical Chemistry, Volume 397, Number 3, 1225-1233, DOI: 10.1007/s00216-010-3636-5). 4-methyl-ephedrine is a potent adrenergic agent and vasoconstrictor, with a therapeutic index a couple to a few times more narrow than ephedrine's, and a duration outlasting mephedrone itself by a few times."
The reference given does not in fact show a 4-methylephedrine metabolite (though 4-methylnorephedrine is shown). Nor can I find any other source for this claim - the two papers on pubmed that mention 4-methylephedrine are both about forensic detection of mephedrone and its metabolites in hair and make the assumption that 4-methylephedrine is likely to be one. The first paper fails to find the metabolites in any of the samples in the analysis, while the second uses blank hair spiked with the chemicals and uses this to validate their method, so neither of these provide any evidence.
Since there is no evidence to support this claim of a cardiotoxic metabolite (or really for the claims made about 4-methylephedrine; pubmed is suspiciously silent on the matter and the description given in the article is strangely vague), these references should be removed.
"Research very strongly suggests mephedrone's cardio-toxicity, but its neurotoxicity as well (see section on current research)."
"In "Beta-keto amphetamines: studies on the metabolism of the designer drug mephedrone and toxicological detection of mephedrone, butylone, and methylone in urine using gas chromatography–mass spectrometry", Meyer et al. confirmed that mephedrone metabolizes to 4-methyl-ephedrine, a highly cardiotoxic compound (2010, Analytical and Bioanalytical Chemistry, Volume 397, Number 3, 1225-1233, DOI: 10.1007/s00216-010-3636-5). 4-methyl-ephedrine is a potent adrenergic agent and vasoconstrictor, with a therapeutic index a couple to a few times more narrow than ephedrine's, and a duration outlasting mephedrone itself by a few times."
The reference given does not in fact show a 4-methylephedrine metabolite (though 4-methylnorephedrine is shown). Nor can I find any other source for this claim - the two papers on pubmed that mention 4-methylephedrine are both about forensic detection of mephedrone and its metabolites in hair and make the assumption that 4-methylephedrine is likely to be one. The first paper fails to find the metabolites in any of the samples in the analysis, while the second uses blank hair spiked with the chemicals and uses this to validate their method, so neither of these provide any evidence.
Since there is no evidence to support this claim of a cardiotoxic metabolite (or really for the claims made about 4-methylephedrine; pubmed is suspiciously silent on the matter and the description given in the article is strangely vague), these references should be removed.