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Dextromethorphan Facts

Dissociative; Substituted morphinan; NMDA receptor antagonist

Description

DXM (dextromethorphan) is a synthetic dissociative of the morphinan class. It blocks glutamate signaling in the brain[1] and inhibits serotonin reuptake,[2] producing its characteristic dissociation and euphoria.

Subjective effects include dissociation, euphoria, time alteration, derealization, and vivid hallucinations at higher amounts. The experience escalates through dose-dependent stages — from mild stimulation to a profound mind-body separation — with a warmer, more euphoric character than ketamine.

Both physical and psychological dependence develop with chronic use,[3][4] and no human lethal dose has been established. The primary acute danger is combining DXM with serotonergic drugs — MAOIs in particular can trigger a life-threatening overheating and seizure response;[5] genetic variation in liver metabolism means identical doses affect people very differently.[6]

Dose and durationby route · individual sensitivity varies

Oral(mg)
Threshold< 75 mgLight100 – 200 mgCommon200 – 400 mgStrong400 – 700 mgHeavy700+ mg

Starts in 30 – 120 minLasts 8 – 12 hoursAfter-effects 4 – 24 hours

Body and dependence

Acute toxicity
Moderate
Chronic toxicity
Moderate
Physical dependence
Low
Psychological dependence
Moderate
Withdrawal
Mild
Compulsive redosing
Low

Tolerance

Builds
Moderate
Fully resets after
10 days
Carries over to
ketamine; PCP; nitrous oxide; memantine

Effectslikely at a common dose

Perception
none likely · 30 possible, including Spatial disorientation, Vestibular distortion, Visual acuity suppression
Body
Motor control impairment; +27 possible, including Nystagmus (eye wobbles), Dizziness, Nausea
Thinking
Cognitive impairment; Decision impairment; +25 possible, including Analysis suppression, Confusion, Memory suppression
Feeling
none likely · 7 possible, including Anxiety, Emotional lability
Self
none likely · 8 possible, including Derealization, Depersonalization, Communication suppression
Time
none likely · 4 possible, including Temporal disorientation
Awareness
none likely · 3 possible

Who shouldn't take it

Absolute
MAOI use
Relative
Respiratory compromise; Serotonergic medication use; Psychotic disorders; Hepatic impairment; CYP2D6 poor metabolizer status; Pregnancy and breastfeeding

Combinations64 recorded

Lethal (8)
Benzodiazepines, Barbiturates; GHB, Baclofen; GHB, GBL; Local anesthetics; MDMA; PCP; Tramadol; αMT
Dangerous (39)
Alpha-2 adrenergic receptor antagonist; Amphetamines; Antihistamines; Benzodiazepines; Buprenorphine, Kratom; Cannabis, THC; Gabapentin, Pregabalin; MAOIs; MDMA, Amphetamines; Naltrexone; NRIs; NSAIDs; Stimulants; THC; 5-HTP, Tryptophan; Anticholinergics; Antipsychotics; Atypical antipsychotics; Buspirone; Caffeine; CBD; Clonidine, Guanfacine; Dopamine agonists; DXM; and 15 more, see full page
Caution (14)
See full page: psychedex.org/substances/dextromethorphan
Not graded (3)
Not listed never means safe.

Seek help immediately if

  • Severe disorientation; unable to move or speak (deep dissociation / "k-hole")
  • Complete loss of coordination — cannot stand or walk safely
  • Vomiting while incapacitated (choking / aspiration risk)
  • Very high blood pressure; fast heart rate
  • Slow or shallow breathing at high doses (especially mixed with depressants)
  • Unconsciousness; rarely, seizures

What to do

  1. Move them somewhere safe, away from stairs, water, roads, and sharp edges — they cannot protect themselves
  2. Place in the recovery position if vomiting or unconscious (aspiration is a key risk)
  3. Stay with them and reassure calmly; keep the environment quiet
  4. If breathing is slow/shallow or they are unresponsive, call emergency services
  5. Do not let them wander; do not leave them alone
  6. Be ready to give rescue breaths / CPR

Effects wear off with time in a safe, monitored setting. The main dangers are physical injury and aspiration while incapacitated, and respiratory depression when combined with other depressants — not the dissociation itself.

988 Suicide & Crisis LifelineFireside Project: 62-FIRESIDE

Version r1 · Not medical advice

References

  1. [1]
    ^Chou YC, Liao JF, Chang WY, Lin MF, Chen CF (1999) Binding of dimemorfan to sigma-1 receptor and anticonvulsant effects compared with dextromethorphan and dextrorphan — Brain Research PMID:10064839
  2. [2]
    ^Werling LL, Keller A, Frank JG, Nuwayhid SJ (2007) A comparison of the binding profiles of dextromethorphan, memantine, fluoxetine and amitriptyline: treatment of involuntary emotional expression disorder — Experimental Neurology PMID:17689532
  3. [3]
    ^Miller SC (2005) Dextromethorphan psychosis, dependence and physical withdrawal — Addiction Biology PMID:16318953
  4. [4]
    ^Mutschler J, Koopmann A, Grosshans M, Hermann D, Mann K, Kiefer F (2010) Dextromethorphan withdrawal and dependence syndrome — Deutsches Arzteblatt International doi:10.3238/arztebl.2010.0537
  5. [5]
    ^Jaffe R et al. (2024) Dextromethorphan (StatPearls) Link
  6. [6]
    ^Schadel M, Wu D, Otton SV, Kalow W, Sellers EM (1995) Pharmacokinetics of dextromethorphan and metabolites in humans: influence of the CYP2D6 phenotype and quinidine inhibition — Journal of Clinical Psychopharmacology PMID:7593709
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