Mephedrone (methylmethcathinone) in toxicology casework: a Northern Ireland perspective.

Mephedrone (4-methylmethcathinone) is the beta-keto analogue of 4-methylmethylamphetamine. Before its control in April 2010, it became popular as a legal high in the United Kingdom, displacing methylenedioxymethylamphetamine as the stimulant drug of choice. The drug has stimulant and psychoactive properties, and therefore has forensic significance in criminal and morbid toxicology. The purpose of this study was to survey casework involving the drug (impaired driving and sudden death). The cases were received in the laboratory for analysis between late 2009 and the end of 2010. Analysis of blood samples for mephedrone was conducted by liquid chromatography-mass spectrometry (LC-MS). Routine screening for alcohol and a range of other pharmaceuticals and drugs of abuse was conducted using a combination of enzyme-linked immunoassay, gas chromatography (GC) headspace, GC-MS and high-performance liquid chromatography with diode array detection. Mephedrone was detected in a total of 12 fatal cases. Most of these cases involved death by mechanical means; in two cases, death was attributed directly to mephedrone intoxication (blood concentrations of 2.1 and 1.94 mg/L). Mephedrone was detected in a total of 32 impaired driving cases. Blood concentrations ranged up to 0.74 mg/L (mean 0.21, median 0.10). The casework evidence in this study indicated that recreational use of the drug can produce to blood levels as high as 0.74 mg/L, although the most common value encountered is likely to lie between 0.2 and 0.3 mg/L.