Dextromethorphan

DXM

Dextromethorphan (DXM) is a morphinan-class dissociative commonly found in over-the-counter cough suppressants.¹² First approved by the FDA in 1957, it acts primarily as a prodrug, with most dissociative effects mediated by its metabolite dextrorphan through NMDA receptor antagonism. Despite its structural similarity to opioids like codeine, dextromethorphan lacks significant mu-opioid receptor activity.¹ Its widespread availability in household cold medicines has made it one of the most accessible dissociatives, contributing to its prevalence as a recreationally misused substance.³

Dextromethorphan

DXM

Psychoactive Class

Dissociative Hallucinogen

Chemical Class

Morphinan

Dosage & Duration

Dosage

Threshold~75 mg

Light75-200 mg

Moderate200-500 mg

Strong500-750 mg

Heavy750+ mg

Bioavailability

11%~⁴

This dosage scale applies to DXM HBr, adjust accordingly to molecular mass. DXM polistirex requires ion exchange to free DXM from the polymer it is bound to, resulting in greatly increased duration and onset akin to that of long-release formulations. To match the peak plasma concentration (and thus effects) of DXM HBr with Polistirex, around double the dose is required.

Duration

Onset30-120 minutes

Come Up1-2 hours

Peak3-6 hours

Offset2-4 hours

After Effects4-24 hours

Total6-12 hours

Half-life

3-30 hours

Subjective Effects

Effects vary widely by individual, dose, and context.

Physical

The subjective physical effects of DXM can be broken down into nine components all of which progressively intensify proportional to dosage.

Disconnection from tactile inputPhysical autonomy

Cognitive

The head space of DXM is often described as particularly impairing, disorientating and generally less clear headed in comparison to that of MXE and Ketamine.

Disconnection from consciousness Ego suppression, loss and death Time distortion Introspection Deja-Vu Removal of cultural filter Conceptual thinking Direct communication with the subconscious States of unity and interconnectedness

Visual

This substance does not enhance visual stimuli; instead it tends to degrade and decrease visual aptitude in a variety of ways.

Distortions

DXM exhibits a full array of dissociative distortions and alterations in visual perception.

Perspective distortions Environmental cubismEnvironmental orbismScenery slicing

Geometry

The visual geometry found within DXM can be described as intricate in complexity, fast in movement, soft in edges, rounded and angular in corners, large in size, immersive in presence and very brightly coloured in scheme when compared to that of MXE.

Hallucinatory States

At high dosages, DXM can produce a full range of high level hallucinatory states in a fashion that is less consistent and reproducible than that of many other commonly used psychedelics.

External hallucinations

Suppressions

Decreased visual acuity Suppression of pattern recognition Blurred vision Double vision

Auditory

The auditory effects of DXM are common in their occurrence and exhibit a range of effects.

Enhancements Suppression Distortions Hallucinations

Forked from Subjective Effect Documentation

by Josie KinsNovember 2012.

Reagent Testing

Expected colorimetric results for common reagent tests. Colors show reaction change over 1–2 minutes.

Marquis(MQ)

Mecke(ME)

Mandelin(MD)

Liebermann(LB)

PROtestkit.eu

Pharmacology

Pharmacodynamics

Dextromethorphan functions primarily as a prodrug of its more potent metabolite dextrorphan, which mediates most of its dissociative effects through uncompetitive NMDA receptor antagonism at the PCP binding site.⁵ The parent compound also contributes directly through strong sigma-1 receptor agonism and serotonin transporter inhibition⁶, with sigma-1 activity potentially contributing to motor effects, tachycardia, and mydriasis. Dextromethorphan additionally acts as a negative allosteric modulator of nicotinic acetylcholine receptors, particularly α3β4 subtypes.⁷ Despite its morphinan structure, dextromethorphan lacks significant mu-opioid receptor activity and does not produce the analgesia, sedation, or respiratory depression typical of related opioid compounds. Published binding affinities vary considerably between studies, with reported values for sigma-1 ranging from 23 to 150 nM and SERT from 40 to over 2000 nM.

Pharmacokinetics

Dextromethorphan is rapidly absorbed from the gastrointestinal tract and undergoes extensive first-pass hepatic metabolism.⁵ The primary metabolic pathway involves O-demethylation via CYP2D6 to the active metabolite dextrorphan⁵, accounting for approximately 80% of dextrorphan formation. A secondary pathway involves N-demethylation via CYP3A4 to 3-methoxymorphinan⁵, which contributes over 90% of that metabolite's production. Both pathways converge on 3-hydroxymorphinan, with subsequent glucuronidation and sulfation. The elimination half-life varies substantially based on CYP2D6 activity, ranging from approximately 4 hours in extensive metabolizers to 13 hours or longer in poor metabolizers. Approximately 1 in 10 individuals of Caucasian descent exhibit reduced CYP2D6 activity.⁹

Interactions

Dangerous

Highest risk

These combinations are considered extremely harmful and should always be avoided. Reactions to these drugs taken in combination are highly unpredictable and have a potential to cause death.

AlcoholAMTGHB/GBLLithiumMAOIsMDMAMephedroneOpioidsPCPSSRIsTramadol

Unsafe

Avoid

There is considerable risk of physical harm when taking these combinations, they should be avoided where possible.

2C-T-x compounds5-MeO-xxT tryptaminesAmphetaminesCocaineDiphenhydramineDOx compoundsMXENBOMe compoundsPregabalin

Caution

Use caution

These combinations are not usually physically harmful, but may produce undesirable effects, such as physical discomfort or overstimulation. Extreme use may cause physical health issues. Synergistic effects may be unpredictable. Care should be taken when choosing to use this combination.

BenzodiazepinesCaffeine

TripSit

Tolerance

Full Tolerance

Tolerance develops with prolonged and repeated use, though the rate varies considerably between individuals. Unlike classical psychedelics, DXM can be used on consecutive days without immediate dramatic tolerance buildup, though regular long-term use will produce tolerance. Some users report an irreversible, permanent tolerance that develops over extended periods of heavy use, potentially correlating with cumulative lifetime doses. Anecdotal reports suggest a threshold around 50 uses after which the characteristic effects may be permanently diminished, though the mechanism remains unclear.

Baseline Reset

1-2 weeks

Half Tolerance

3-7 days

Cross Tolerance

Dissociatives (all NMDA receptor antagonists)

Harm Potential

Addiction & Dependence

Psychological

Low

Psychological addiction is uncommon but documented.¹⁰ Some users develop craving and emotional dependence with regular use, finding it difficult to stop.¹⁰ DXM is considered less addictive than opioid-based cough suppressants like codeine, though it is classified as habit-forming.

Physical

Low

Physical dependence is not well-established.¹⁰ Long-term regular users report withdrawal symptoms similar to antidepressant discontinuation syndrome, including disturbances in sleep, senses, movement, mood, and cognition.¹⁰ Some users report a 1-2 week hangover period after stopping regular use. Life-threatening withdrawal has not been documented.¹⁰

Toxicity

Central Nervous System

Chronic heavy use over extended periods may cause cognitive deficits including impaired episodic memory, learning difficulties, and abnormalities in visual processing and abstract language comprehension;¹⁰ the theory that DXM causes Olney's lesions (brain vacuolization) remains inconclusive in humans, and oral administration in rats did not produce such lesions.¹¹

Cardiovascular

Acute increases in systolic and diastolic blood pressure along with increased heart rate occur at high doses;¹⁰ serious cardiovascular events are primarily associated with overdose or products containing stimulant adulterants.

Urinary System

Urinary retention becomes increasingly likely at higher doses and may result in complete inability to urinate at very high doses; this is an acute effect during intoxication rather than chronic damage.

Psychosis Risk

Psychotic symptoms including delusions, paranoia, and detachment from reality occur at high doses, particularly at third plateau and above.¹⁰ Plateau sigma (extended high-dose sessions) carries high risk of delirium and psychosis. Extended heavy use over days or weeks may cause lasting delusional, paranoid, and psychotic ideation persisting for weeks, months, or longer after cessation.¹⁰

Seizure Risk

Seizures have been reported in overdose scenarios.¹³ Many reported seizure cases involve adulterants such as chlorpheniramine maleate rather than DXM itself.¹⁰ States of agitation with epileptic episodes may occur at very high doses.

History & Culture

Discovery and Development

The racemic parent compound racemethorphan was first described in patent applications by Hoffmann-La Roche in Switzerland and the United States in 1946 and 1947, respectively, with a patent granted in 1950. Resolution of the two isomers using tartaric acid was published in 1952. Dextromethorphan…

Trip Reports

Legality

By Country

United StatesUnscheduled

At the federal level, the Controlled Substances Act does not include dextromethorphan in any schedule, so DXM itself is not subject to the Act’s controlled-substance controls. FDA’s OTC Monograph M012 includes dextromethorphan and dextromethorphan hydrobromide for eligible nonprescription cold and cough products; FDA product requirements and separate state retail restrictions remain distinct from federal CSA scheduling.

AustriaUnscheduled (Pharmacy Only)

Not listed in the Suchtmittelgesetz (Federal Law on Narcotics). Sales restricted to pharmacies but preparations are available without prescription.

BrazilUnscheduled

Dextromethorphan is expressly excluded from the Lista A1 controls that otherwise extend to salts, ethers, esters, and isomers of listed narcotic substances. It is not listed in the current controlled-substances annex. ANVISA lists dextromethorphan hydrobromide oral solution up to 3 mg/mL as a non-prescription medicine for specified cough indications.

ChinaRestricted

Dextromethorphan is retained as a Class II psychotropic drug in the Medicinal Psychotropic Drugs Catalogue (2025 Edition); Class II control began on 1 July 2024. The catalogue covers possible salts and single-ingredient preparations unless otherwise specified. Production, distribution, use, storage, and transport are prohibited except through the regulated system; retail sale requires a physician’s prescription and prescribed quantity, and sales without a prescription or to minors are prohibited.

Czech RepublicMixed (Formulation Dependent)

Some pharmacies require prescription for tablet formulations while liquid preparations may be available without prescription.

EgyptPrescription Only

Since 8 August 2021, preparations containing dextromethorphan, its salts, or its derivatives as the sole active ingredient at any concentration are classified in Schedule I. They may be supplied only under the Schedule I psychotropic-medicine controls, including prescribed dispensing; combination preparations containing more than 30 mg per single dose are Schedule II, while remaining combinations are outside those entries.

FinlandPharmacy Only (OTC)

Listed in the medicinal product list and restricted to pharmacy sales. Can be purchased without prescription and without age restriction. Some products require a permit to sell.

GermanyUnscheduled (Pharmacy Only)

Not listed in the Betäubungsmittelgesetz (Federal Law on Narcotics). Sales restricted to pharmacies but available without prescription in syrup and tablet forms.

HungaryMixed (Formulation Dependent)

Cough syrups containing DXM available over-the-counter. Pure DXM capsules require a prescription.

IranOTC

DXM-only and DXM combination products available over-the-counter without prescription.

ItalyUnscheduled

Dextromethorphan is expressly excluded from Table I of the tables attached to Presidential Decree No. 309/1990, which lists controlled narcotic and psychotropic substances. It is not scheduled in those controlled-substance tables.

LatviaProhibited/Restricted

Among the few countries where DXM-containing antitussive preparations face significant restrictions beyond standard pharmacy controls.

MexicoUncontrolled

Not listed in the General Health Law (Ley General de Salud) as a controlled substance. Classified as a category VI drug under Article 226, meaning DXM-only products can be sold without prescription at any retailer, including non-pharmacy establishments.

New ZealandOTC

Available over-the-counter without identification requirements. Products including Robitussin Dry Cough Forte widely available.

PhilippinesLegal (Regulated)

The Philippine FDA classifies dextromethorphan as PH, a Pharmacist-Only Non-Prescription Pharmaceutical Product. It may be supplied without a prescription only through a pharmacist.

PortugalUnscheduled

Dextromethorphan is expressly excluded from Table I-A of Decree-Law No. 15/93, Portugal’s controlled-substances schedule. INFARMED lists dextromethorphan products among non-prescription medicines not reimbursed by the National Health Service.

RussiaSchedule III

Listed as a Schedule III controlled substance following government anti-DXM campaigns. Subject to tighter restrictions than in most other countries.

South AfricaLegal (Regulated)

Dextromethorphan is listed in Schedule 2 of the Schedules made under the Medicines and Related Substances Act. Schedule 2 medicines may be sold without a prescription only by a pharmacist or pharmacy personnel under a pharmacist’s personal supervision, and each sale is subject to the Act’s recording requirements.

SwedenIllegal

Dextromethorphan has been classified as a narcotic in Sweden since 1 September 2008 and remains listed in Annex 1 to the Narcotics Control Ordinance under Hallucinogener. Solutions for medical or scientific use containing no more than 3 mg/mL are exempt. Unlawful possession, use, manufacture, or transfer of non-exempt dextromethorphan is a narcotics offence punishable by up to three years’ imprisonment.

ThailandRestricted

Dextromethorphan is a Dangerous Drug in Thailand because the standing notification classifies antitussive drugs other than expectorants as Dangerous Drugs; the Thai FDA identifies dextromethorphan as such a drug. The antitussive provision derives from the 26 May 1978 notification and was amended on 2 August 2007; the FDA’s current consolidated register retains it. Under section 32 of the Drug Act, a licensee may not sell a Dangerous Drug while a pharmacist is not on duty; dextromethorphan medicines also require dangerous-drug sales records.

United KingdomPharmacy Only Medication

Specifically exempted from control under the Misuse of Drugs Act 1971 and 2001.¹⁸ Restricted to pharmacy sales at the discretion of the pharmacist. Purchasers typically must be at least 16 years of age. Multiple purchases may be refused or questioned.

AustraliaPharmacy Medicine (OTC)

Available over-the-counter from pharmacies. Import restrictions may apply to DXM-only products. Robitussin Dry Cough Forte is among the available DXM-only preparations.

BelgiumOTC

Available over-the-counter without prescription and without age restriction. DXM-only products available at some pharmacies.

CanadaExempt from CDSA

Specifically listed as exempt from the Controlled Drugs and Substances Act. Available over-the-counter without prescription and can legally be obtained in powder form.

ColombiaLegal (Regulated)

INVIMA’s list of over-the-counter medicines includes formulations of dextromethorphan hydrobromide, including syrups, tablets, suspensions, and dispersible films. Those formulations are authorised as non-prescription medicines in the concentrations and pharmaceutical forms specified by the list.

DenmarkPrescription Type A

The DXM-containing product Dexofan is classified as a prescription type A medication, requiring a doctor's prescription for purchase.

EstoniaProhibited/Restricted

Among the few countries where DXM-containing antitussive preparations face significant restrictions beyond standard pharmacy controls.

FrancePrescription Only

Since 17 July 2017, the order removes the French poisonous-substances-regulation exemption for medicines containing dextromethorphan and its salts. Authorised dextromethorphan medicines are therefore subject to the Liste I prescription regime and are dispensed only on prescription. Dextromethorphan is expressly excluded from the current French narcotics entry for levomethorphan's dextrorotatory isomer.

Hong KongPharmacy Only (ID Required)

Does not require a prescription but purchasers must provide identification to the pharmacy. Some product lines have been discontinued from the market.

IndonesiaRestricted

Dextromethorphan is listed as an Obat-Obat Tertentu under Peraturan BPOM No. 12 of 2025, which has applied since 2 May 2025. The regulation controls its procurement, storage, distribution, dispensing, and destruction, and provides for administrative sanctions for breaches.

IsraelOTC

Available in popular over-the-counter cough medicines without prescription.

JapanLegal (OTC)

DXM is legal and has been available in various retail settings. Historically sold in specialized shops.

MalaysiaControlled Medication

Classified as a controlled medication available from pharmacies and clinics. Recreational use is explicitly prohibited under law.

NetherlandsLegal (Regulated)

Dextromethorphan-containing self-care medicines have held the UA (Uitsluitend Apotheek) dispensing status since 2008. UA medicines are available without prescription but may be supplied only by pharmacies. Dextromethorphan is expressly excluded from the Opiumwet List I enantiomer catch-all and is not within the current List IA generic NPS groups.

NorwayControlled (Analog Act)

Norway treats dextromethorphan as a narcotic through the blanket stereoisomer rule: it is the psychoactive dextrorotatory stereoisomer of N I-listed levomethorphan. The regulation entered into force on 14 February 2013. Manufacture, import, wholesale and retail supply require statutory authorization, while possession or use without lawful access is prohibited. Unauthorized possession or use is punishable by a fine or imprisonment for up to six months.

PolandOTC (Restricted)

Available over-the-counter in tablet, capsule, and syrup forms. Purchasers must be over 18 years of age and are limited to purchasing no more than 360 mg of DXM per transaction at a single pharmacy.

RomaniaMixed (Formulation Dependent)

Pure DXM preparations require a prescription. Liquid formulations and products marketed as Tussin are available over-the-counter, though enforcement varies.

SingaporeClass A Prescription Drug

Classified as a Class A prescription medication. Cannot be purchased without a valid prescription from a physician.

South KoreaRestricted

Dextromethorphan, its salts, and its isomers are listed as a psychotropic drug in Annex 6 to the Narcotics Control Act Enforcement Decree; this listing has applied since 1 October 2003. Under the Narcotics Control Act, a person who is not an authorised narcotics handler may not possess, use, transport, manage, import, export, manufacture, dispense, administer, transfer, sell, or provide it, subject to statutory exceptions for lawful handling.

SwitzerlandAbgabekategorie B (Prescription)

Classified as a category B pharmaceutical, generally requiring a prescription or pharmacist consultation. Reclassified in 2018 from category C, which had previously allowed over-the-counter purchase.

TurkeyPrescription Only

DXM-only products require a prescription for purchase. Availability may be limited.

References

Source Pages

Citations

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