Mephedrone (4-MMC)

Mephedrone, also called 4-methylmethcathinone or 4-MMC, is a synthetic stimulant of the cathinone class. Cathinones are chemically related to the natural stimulant found in the khat plant (Catha edulis) of East Africa; mephedrone is a laboratory-made member of this family and a beta-keto analogue of an amphetamine. It first appeared on the recreational drug market around 2007-2009, sold online and in "head shops" as a legal alternative to MDMA (ecstasy) and cocaine, and became widely used before being banned. It usually comes as a white or off-white powder or in capsules, and people typically swallow it, wrap it in paper and swallow it ("bombing"), or snort it; injecting also occurs and is especially dangerous. Common street names include drone, M-CAT, meow meow, and bubble.

Mephedrone works by acting on the brain's monoamine systems — the same broad targets as MDMA, amphetamines, and cocaine. It is a non-selective monoamine releaser and reuptake inhibitor, meaning it both triggers release of and blocks the reabsorption of dopamine, norepinephrine, and serotonin. Its balance between dopamine and serotonin effects (a dopamine-to-serotonin transporter ratio of roughly 1.4) sits between that of cocaine and MDMA, which is why users often describe it as a mixed "MDMA-cocaine-like" drug — part euphoric stimulant, part empathogen. In this respect it acts as a releaser, similar to methylone, and differently from MDPV, which mainly blocks reuptake without triggering release. Its effects come on quickly and are relatively short-lived, which contributes to the strong tendency to redose.

People report that mephedrone produces euphoria, increased energy and alertness, talkativeness, feelings of warmth and closeness to others, and heightened sociability — an effect profile overlapping ecstasy and cocaine. Onset is rapid and the main effects are short-lasting, often less than an hour, which drives a strong and well-documented urge to take repeated doses in a session. Common unwanted effects include jaw clenching, teeth grinding, sweating, dilated pupils, raised heart rate and blood pressure, agitation, and difficulty sleeping.

Mephedrone's central risks come from over-stimulation of the cardiovascular and nervous systems (sympathomimetic toxicity): rapid or irregular heartbeat, chest pain, dangerously high blood pressure, overheating, agitation, and, in severe cases, seizures. Because effects are short and intense, compulsive redosing is common and raises the total dose and the strain on the body. At least 90 deaths have been documented in which mephedrone alone or combined with other substances was implicated, and the risk climbs sharply when it is mixed with other stimulants, alcohol, or depressants, or when it is injected. Repeated heavy use is associated with anxiety, paranoia, low mood, and dependence. As with other cathinones sold as powders, actual purity and contents vary and a product sold as one cathinone may be another.