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Mephedrone Facts

Stimulant; Entactogen; Substituted cathinone; Monoamine releasing agent

Description

Mephedrone (4-methylmethcathinone) — meow meow, meph, M-CAT — is a synthetic stimulant-empathogen of the substituted cathinone class. It floods the brain with dopamine, norepinephrine, and serotonin simultaneously, producing both stimulant energy and emotional warmth.[1][2]

Subjective effects include euphoria, emotional warmth, empathy, tactile enhancement, heightened energy, and thought acceleration. The experience sits between amphetamine and MDMA — stimulant drive and entactogenic closeness combined in a way neither compound produces alone.

Mephedrone carries notable abuse liability — effects fade quickly, driving compulsive redosing.[3] Cardiovascular overload and serotonin syndrome — a life-threatening overheating and muscle rigidity response — are the primary acute risks, amplified in hot environments or by serotonergic drugs.[4][5]

Dose and durationby route · individual sensitivity varies

Oral(mg)
Threshold< 15 mgLight25 – 75 mgCommon75 – 150 mgStrong150 – 250 mgHeavy300+ mg

Starts in 15 – 45 minLasts 3 – 5 hoursAfter-effects 2 – 6 hours

Body and dependence

Acute toxicity
Moderate
Chronic toxicity
Moderate
Physical dependence
Low
Psychological dependence
Moderate
Withdrawal
None recorded
Compulsive redosing
High

Tolerance

Builds
Moderate
Fully resets after
10 days
Carries over to
MDMA; amphetamine; methamphetamine; methylone; cocaine

Effectslikely at a common dose

Perception
Music enhancement; +5 possible, including Tinnitus
Body
Wakefulness; Stimulation; Abnormal heartbeat; Appetite suppression; Body high; Physical fatigue; +27 possible, including Bruxism, Dehydration sensation, Vasoconstriction
Thinking
Thought acceleration; Compulsive redosing urge; Cognitive euphoria; +25 possible, including Cognitive dysphoria, Cognitive impairment, Decision impairment
Feeling
Euphoria; +11 possible, including Depression, Anhedonia, Anxiety
Self
none likely · 10 possible, including Craving, Ego inflation, Compulsive repetitive behavior
Time
none likely · 2 possible
Awareness
none likely · 2 possible

Who shouldn't take it

Absolute
Pre-existing cardiovascular disease; Concurrent serotonergic medication; Psychotic disorders; CYP2D6 poor/intermediate metabolizer status; Pregnancy and breastfeeding
Relative
Hot/warm environments; Alcohol co-use

Combinations62 recorded

Lethal (3)
Ibogaine; MAOIs; Tramadol
Dangerous (35)
Alpha-2 adrenergic receptor antagonist; Amphetamines; Benzodiazepines, Barbiturates; Ephedrine, Pseudoephedrine; GHB, GBL; Local anesthetics; MDMA, Amphetamines; MDMA, MDA; NDRIs (Wellbutrin); NRIs; Opioids; SSRIs; Stimulants; 5-HTP, Tryptophan; Anticholinergics; Antihistamines; Antipsychotics; Atypical antipsychotics; Buspirone; Caffeine; Clonidine, Guanfacine; Dopamine agonists; DXM; GHB, Baclofen; and 11 more, see full page
Caution (20)
See full page: psychedex.org/substances/mephedrone
Not graded (4)
Not listed never means safe.

Seek help immediately if

  • Overheating / very high body temperature — heavy sweating, then hot dry skin (the leading cause of MDMA deaths, worse when dancing in hot venues)
  • Muscle rigidity, jaw clenching, tremor, or twitching (possible serotonin syndrome)
  • Fast, pounding heartbeat; chest pain
  • Agitation, confusion; seizures
  • Hyponatremia (water intoxication) — headache, confusion, drowsiness, vomiting, and seizures from drinking too much water
  • Nausea/vomiting; collapse or unconsciousness

What to do

  1. Move them somewhere cool and help them cool down — overheating is the main danger
  2. Sip water to stay hydrated but DO NOT overdrink — roughly a cup (250 ml) per hour if active; too much water can be deadly (hyponatremia)
  3. Get them to rest and stop dancing
  4. For overheating, seizures, chest pain, muscle rigidity/tremor, confusion, or unresponsiveness, call emergency services
  5. Recovery position if drowsy or vomiting; stay with them
  6. Be ready to give rescue breaths / CPR

Most resolve with cooling, rest, sensible hydration, and time. The life-threatening dangers are hyperthermia, serotonin syndrome, and hyponatremia (too much water) — each a medical emergency, not something to wait out.

988 Suicide & Crisis LifelineFireside Project: 62-FIRESIDE

Version r1 · Not medical advice

References

  1. [1]
    ^Baumann MH, Ayestas MA, Partilla JS, et al. (2012) The designer methcathinone analogs, mephedrone and methylone, are substrates for monoamine transporters in brain tissue — Neuropsychopharmacology doi:10.1038/npp.2011.304
  2. [2]
    ^Simmler LD, Buser TA, Donzelli M, et al. (2012) Pharmacological characterization of designer cathinones in vitro — British Journal of Pharmacology doi:10.1111/j.1476-5381.2012.02145.x
  3. [3]
    ^Winstock A, Mitcheson L, Ramsey J, et al. (2011) Mephedrone: use, subjective effects and health risks — Addiction doi:10.1111/j.1360-0443.2011.03502.x
  4. [4]
    ^Meng H, Cao J, Kang J, et al. (2012) Mephedrone, a new designer drug of abuse, produces acute hemodynamic effects in the rat — Toxicology Letters doi:10.1016/j.toxlet.2011.10.010
  5. [5]
    ^Garrett G, Sweeney M (2010) The serotonin syndrome as a result of mephedrone toxicity — BMJ Case Reports doi:10.1136/bcr.04.2010.2925
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