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    Dextromethorphan molecular structure

    Dextromethorphan Stats & Data

    Depressant Dissociative Research-chemical
    Dm Dxm Dex Robo Syrup robotussin robitussin
    NPS DataHub
    MW271.4
    FormulaC18H25NO
    CAS125-71-3
    IUPAC(1S,9S,10S)-4-methoxy-17-methyl-17-azatetracyclo[7.5.3.01,10.02,7]heptadeca-2(7),3,5-triene
    SMILESCOc1ccc2CC3N(C)CCC4(CCCCC34)c2c1
    InChIKeyMKXZASYAUGDDCJ-NJAFHUGGSA-N
    Chemical Class Phenethylamine
    Psychoactive Class Depressant / Dissociative
    Half-Life Highly variable: ~2.4 h (extensive metabolizers) to ~19 h (poor metabolizers) for DM; ER polistirex prolongs absorption and effect window without changing intrinsic elimination. Apparent total effect can run 8–14+ h.

    Interaction Warnings

    ⚠ stimulants

    A dangerous rise in blood pressure and heart rate can occur when DXM is combined with a stimulant such as amphetamine and/or cocaine.

    Pharmacology

    DrugBank
    State Solid

    Description

    Dextromethorphan is a levorphanol derivative and codeine analog commonly used as a cough suppressant and also a drug of abuse. Although similar in structure to other opioids, it has minimal interaction with opioid receptors. Dextromethorphan was granted FDA approval before 3 December 1957.

    Mechanism of Action

    Dextromethorphan is an agonist of NMDA and sigma-1 receptors. It is also an antagonist of α3/β4 nicotinic receptors. However, the mechanism by which dextromethorphan's receptor agonism and antagonism translates to a clinical effect is not well understood.

    Pharmacodynamics

    Dextromethorphan is an opioid-like molecule indicated in combination with other medication in the treatment of coughs and pseudobulbar affect. It has a moderate therapeutic window, as intoxication can occur at higher doses. Dextromethorphan has a moderate duration of action. Patients should be counselled regarding the risk of intoxication.

    Metabolism

    Dextromethorphan can be N-demethylated to 3-methoxymorphinan by CYP3A4, CYP2D6, and CYP2C9 or O-demethylated to dextrorphan by CYP2D6 and CYP2C9. Dextrorphan is N-demethylated by CYP3A4 and CYP2D6, while 3-methoxymorphinan is O-demethylated by CYP2D6. Both are metabolized to form 3-hydroxymorphinan. Dextrorphan and 3-hydroxymorphinan are both O-glucuronidated or O-sulfated.

    Absorption

    A 30mg oral dose of dextromethorphan reaches a Cmax of 2.9 ng/mL, with a Tmax of 2.86 h, and an AUC of 17.8 ng\*h/mL.

    Toxicity

    A dextromethorphan overdose may present as nausea, vomiting, stupor, coma, respiratory depression, seizures, tachycardia, hyperexcitability, toxic psychosis, ataxia, nystagmus, dystonia, blurred vision, changes in muscle reflexes, and serotonin syndrome. Overdose should be managed through symptomatic and supportive measures.

    Indication

    Dextromethorphan is indicated in combination with brompheniramine and pseudoephedrine in the treatment of coughs and upper respiratory symptoms associated with allergies or the common cold. Dextromethorphan is also used in combination with guaifenesin as an over-the-counter product to relieve a cough. Dextromethorphan in combination with quinidine is indicated in the treatment of pseudobulbar affect.

    Half-life

    Dextromethorphan has a half life of 3-30 hours.

    Protein Binding

    Dextromethorphan is 60-70% protein bound in serum.

    Volume of Distribution

    The volume of distribution of dextromethorphan is 5-6.7L/kg.

    Metabolites

    Dextrorphan (active, primary mediator of dissociative effects, approximately 10x more potent NMDA antagonist than parent compound, less active as serotonin reuptake inhibitor)
    3-Methoxymorphinan (local anesthetic effects, CYP2D6 inhibitor)
    3-Hydroxymorphinan (neuroprotective and neurotrophic effects)

    Receptor Profile

    Receptor Actions

    Agonists
    Sigma-1 receptor agonist
    Antagonists
    NMDA receptor antagonist (uncompetitive)
    Nicotinic acetylcholine receptor antagonist
    Inhibitors
    Serotonin-norepinephrine reuptake inhibitor (SNRI)

    Receptor Binding

    SERT 40 nM (DXM), 484 nM (DXO)
    Sigma-1 150 nM (DXM), 118 nM (DXO)
    NET 6000 nM (DXM), 6200 nM (DXO)
    NMDA 2120 nM (DXM), 892 nM (DXO)
    α1D-adrenergic 830 nM (DXM)
    α1A-adrenergic 3000 nM (DXM)
    Sigma-2 11,060 nM (DXM), 11,325 nM (DXO)

    History & Culture

    1946–1958

    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 was subsequently patented in the United States in 1954 by Hoffmann-La Roche after research in the early 1950s demonstrated its antitussive properties in animal studies. The compound received FDA approval in 1958 and was introduced as an over-the-counter cough suppressant, becoming a popular alternative to codeine-based preparations.

    1954–1964

    The U.S. federal government conducted research seeking a non-addictive codeine alternative through a program known as MKPILOT. This work was completed at the Addictive Research Center, part of the U.S. Public Health Service Hospital in Lexington, Kentucky, where a researcher tested approximately 800 drugs on patients with addiction, including dextromethorphan. The research was partially funded through CIA involvement, with at least $282,215 transferred to the Office of Naval Research as part of U.S. Navy and CIA-funded investigations into nonaddictive substitutes for codeine. The CIA's interest in this research was classified as secret.

    1960–1975

    The first recorded instances of recreational dextromethorphan use date to 1962. During this period, the substance became available in an over-the-counter tablet form marketed under the brand name Romilar. In the early 1960s, figures associated with the Beat movement and counterculture experimented with dextromethorphan in its Romilar formulation, including poets Allen Ginsberg and Peter Orlovsky, musician Daevid Allen of Soft Machine, and author Jack Kerouac. Reports of recreational use emerged internationally by the mid-1960s, with documented use among young people near Brisbane, Australia around 1968 to 1969, who described perceptual changes, visual hallucinations, and altered temporal perception. By 1973, growing misuse within the counterculture prompted the voluntary withdrawal of Romilar tablets from the market following a significant burst in sales. Manufacturers subsequently introduced cough syrup formulations designed to deter abuse. Dextromethorphan was specifically excluded from the 1970 Controlled Substances Act to prevent its classification as an analog of levomethorphan, a Schedule II substance with opioid activity. The popularity and extensive abuse of dextromethorphan was formally recognized by 1975.

    1986–present

    In response to abuse concerns, several countries implemented stricter controls. In 1986, the Swedish National Board of Health and Welfare reclassified dextromethorphan as a prescription medication due to teenage abuse. Indonesia became the only country to prohibit single-component dextromethorphan entirely, with the National Agency of Drug and Food Control banning such sales both over-the-counter and by prescription.

    1990–2010

    The widespread adoption of internet access during the 1990s facilitated rapid dissemination of information about dextromethorphan, with online discussion groups forming around its use and acquisition. Usenet became an active forum for discussing the substance's properties and extraction methods from commercial syrups. By 1996, pure dextromethorphan hydrobromide powder became available from online chemical vendors, allowing users to circumvent syrup preparations. The early 2000s saw a significant rise in nonmedical use, particularly among adolescents. California reported elevated rates of misuse from 1999 to 2004, while Texas rave parties reportedly featured dextromethorphan as an alternative to MDMA. Analysis by DanceSafe between February 1999 and March 2000 found that 21% of pills sold as MDMA or ecstasy actually contained dextromethorphan. In 2004, the DEA conducted Operation Web Tryp, a large-scale enforcement action that significantly reduced online availability of pure dextromethorphan powder. In 2010, the FDA approved a combination of dextromethorphan and quinidine for the treatment of pseudobulbar affect. That same year, the FDA's Drug Safety and Risk Management Committee voted 15-9 against scheduling dextromethorphan despite documented nonmedical use. According to the Consumer Healthcare Products Association, approximately 90% of nonprescription cough medicines contain dextromethorphan, with 133 million packages sold in the United States in 2009. The DEA continues to classify it as a drug of concern due to its widespread availability to adolescents and young adults.

    Subjective Effect Notes

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

    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.

    Effect Profile

    Curated + 802 Reports
    Dissociative 5.9

    Moderate dissociative depth, motor impairment, and insight with mild mania

    Dissociative Depth×3
    74.1 6/25
    Mania / Compulsion×1
    52.9 6/25
    Insight / Novel Thought×2
    60.7 6/25
    Motor / Sensory Impairment×1
    74.2 5/25
    Catalog Erowid

    User Experiences

    Dissociative Depth "If I do a huge line, I will k-hole." — Bluelight ↗
    Motor Impairment "I had double vision, couldn't walk very well, couldn't read, could sorta talk but too fast and quite confusedly.." — Bluelight ↗
    Insight "I've been high on large doses (600mg) several times before and very much enjoyed it, and still been able to think with a new kind of insight and clarity." — Bluelight ↗
    Based on reports from:
    Effect Index Re-discovering DXM — Josie Effect Index Heavy Dose of Cough Syrup — Gabriel Effect Index Psychedelic Dissociation — Josie Effect Index Swimming in the Dextroverse — froggie Effect Index To the Dextroverse! — Amethyst Effect Index Nexuswalk - A Beautiful Mix of DXM and 2C-B — LeftoverNinja Effect Index Dying from a Cosmic Slap — froggie Effect Index I Slept for 27 Hours — Julie Bluelight Big & Dandy Thread Erowid Experience Reports PsychonautWiki Dextromethorphan The Drug Users Bible Dextromethorphan

    Empirical Duration

    Erowid Reports
    Onset Come Up Peak Offset
    Oral (82 reports)

    Community Effects

    TripSit
    Positive
    dissociation
    Negative
    nausea addiction

    Tolerance & Pharmacokinetics

    drugs.wiki
    Half-Life
    Highly variable: ~2.4 h (extensive metabolizers) to ~19 h (poor metabolizers) for DM; ER polistirex prolongs absorption and effect window without changing intrinsic elimination. Apparent total effect can run 8–14+ h.
    Addiction Potential
    Moderate. Repeated use can lead to psychological dependence, especially for dissociative coping or sleep. Physical dependence is uncommon but heavy chronic use can lead to tolerance, compulsive redosing, and withdrawal‑like dysphoria, insomnia, and cravings.

    Tolerance Decay

    Full tolerance 2d Half tolerance 7d Baseline ~21d

    Tolerance to dissociative effects builds rapidly over consecutive days and decays over 1–4+ weeks; values are approximate and largely anecdotal. Cross‑tolerance with other NMDA antagonists is expected but not precisely quantified.

    Cross-Tolerances

    Ketamine
    40% ●○○
    PCP/analogues
    40% ●○○
    Other arylcyclohexylamines (e.g., MXE)
    40% ●○○

    Experience Report Analysis

    Erowid
    802 Reports
    1993–2023 Date Range
    140 With Age Data
    33 Effects Detected

    Demographics

    Gender Distribution

    Age Distribution

    Reports Over Time

    Effect Analysis

    Erowid

    Effects aggregated from 802 experience reports (802 Erowid)

    802 Reports
    33 Effects Detected
    13 Positive
    12 Adverse
    8 Neutral

    Effect Sentiment Distribution

    Confidence Distribution

    Positive Effects 13

    Anxiety Suppression 37.0% 70%
    Music Enhancement 34.3% 70%
    Euphoria 26.4% 70%
    Color Enhancement 24.6% 70%
    Empathy 24.3% 70%
    Stimulation 21.3% 70%
    Tactile Enhancement 19.2% 70%
    Focus Enhancement 17.5% 70%
    Sedation 17.1% 70%
    Introspection 12.6% 70%
    Body High 6.7% 70%
    Creativity Enhancement 4.6% 70%
    Pain Relief 2.1% 70%

    Adverse Effects 12

    Nausea 31.5% 70%
    Confusion 31.4% 70%
    Memory Suppression 13.7% 70%
    Motor Impairment 11.8% 70%
    Pupil Dilation 9.9% 70%
    Sweating 6.6% 70%
    Increased Heart Rate 5.9% 70%
    Psychosis 4.7% 70%
    Muscle Tension 4.4% 70%
    Headache 3.7% 70%
    Seizure 3.0% 70%
    Jaw Clenching 2.1% 70%

    Dose-Response Correlation

    How effect frequency changes across dose levels

    View data table
    Effect Light (n=41) Common (n=130) Strong (n=104) Heavy (n=96)
    Music Enhancement 51.2% 51.5% 42.3% 35.4%
    Visual Distortions 43.9% 51.5% 49.0% 37.5%
    Anxiety Suppression 36.6% 44.6% 38.5% 43.8%
    Confusion 34.1% 33.1% 42.3% 43.8%
    Sedation 41.5% 20.0% 14.4% 22.9%
    Nausea 34.1% 41.5% 36.5% 37.5%
    Dissociation 34.1% 28.5% 38.5% 22.9%
    Stimulation 34.1% 37.7% 19.2% 17.7%
    Euphoria 36.6% 36.2% 33.7% 31.2%
    Color Enhancement 24.4% 30.8% 32.7% 34.4%
    Closed-Eye Visuals 26.8% 30.8% 33.7% 30.2%
    Empathy 31.7% 21.5% 31.7% 22.9%
    Hospital 14.6% 13.8% 20.2% 30.2%
    Tactile Enhancement 29.3% 25.4% 20.2% 16.7%
    Auditory Effects 24.4% 23.8% 26.0% 14.6%

    Subjective Effect Ontology

    Experience Reports

    Structured effect tags extracted from 802 experience reports using a controlled vocabulary of 220+ canonical effects across 15 domains.

    Auditory

    music enhancement 275 34.3% auditory effects 151 18.8%

    Cognitive

    confusion 252 31.4% focus enhancement 140 17.5% memory suppression 110 13.7% introspection 101 12.6%

    Emotional

    anxiety suppression 297 37.0% euphoria 212 26.4% empathy 195 24.3%

    Gastrointestinal

    nausea 253 31.5%

    Motor

    stimulation 171 21.3% sedation 137 17.1%

    Selfhood

    dissociation 198 24.7%

    Tactile

    tactile enhancement 154 19.2%

    Visual

    visual distortions 296 36.9% color enhancement 197 24.6% closed eye visuals 174 21.7% open eye visuals 100 12.5%

    18 unique effects extracted · Derived from experience reports

    Dose–Effect Mapping

    Experience Reports

    How reported effects shift across dose tiers, based on 802 experience reports.

    Oral dose range: 272.0–670.0 mg (median 420.0 mg)
    Effect Light (n=41) Common (n=130) Strong (n=104) Heavy (n=96)
    music enhancement
    51%
    52%
    42%
    35%
    		↓
    visual distortions
    44%
    52%
    49%
    38%
    		→
    anxiety suppression
    37%
    45%
    38%
    44%
    		↑
    confusion
    34%
    33%
    42%
    44%
    		↑
    sedation
    42%
    20%
    14%
    23%
    		↓
    nausea
    34%
    42%
    36%
    38%
    		→
    dissociation
    34%
    28%
    38%
    23%
    		↓
    stimulation
    34%
    38%
    19%
    18%
    		↓
    euphoria
    37%
    36%
    34%
    31%
    		→
    color enhancement
    24%
    31%
    33%
    34%
    		↑
    closed-eye visuals
    27%
    31%
    34%
    30%
    		→
    empathy
    32%
    22%
    32%
    23%
    		↓
    hospital
    15%
    14%
    20%
    30%
    		↑
    tactile enhancement
    29%
    25%
    20%
    17%
    		↓
    auditory effects
    24%
    24%
    26%
    15%
    		↓
    memory suppression
    15%
    14%
    14%
    26%
    		↑
    focus enhancement
    22%
    23%
    24%
    21%
    		→
    introspection
    22%
    13%
    20%
    9%
    		↓
    open-eye visuals
    12%
    15%
    19%
    20%
    		↑
    motor impairment
    7%
    18%
    16%
    17%
    		↑

    Showing top 20 of 35 effects

    Risk Escalation

    Sentiment Analysis

    Average frequency of positive vs adverse effects across dose tiers

    Light n=41
    10 positive 27.1% 14 adverse 14.6%
    Common n=130
    11 positive 23.2% 15 adverse 13.4%
    Strong n=104
    10 positive 23.6% 13 adverse 14.7%
    Heavy n=96
    10 positive 19.5% 12 adverse 18.6%
    View effect breakdown

    Adverse Effects

    Effect Light (n=41) Common (n=130) Strong (n=104) Heavy (n=96) Change
    Anxiety Suppression
    37%
    45%
    38%
    44%
    		+19%
    Confusion
    34%
    33%
    42%
    44%
    		+28%
    Nausea
    34%
    42%
    36%
    38%
    		9%
    Memory Suppression
    15%
    14%
    14%
    26%
    		+78%
    Motor Impairment
    7%
    18%
    16%
    17%
    		+128%
    Pupil Dilation
    12%
    12%
    10%
    16%
    		+27%
    Headache
    12%
    4%
    4%
    3%
    		-74%
    Muscle Tension
    12%
    6%
    7%
    3%
    		-74%
    Sweating
    7%
    7%
    6%
    10%
    		+42%
    Increased Heart Rate
    10%
    7%
    10%
    7%
    		-25%
    Jaw Clenching
    10%
    5%
    		— — -53%
    Psychosis
    5%
    4%
    5%
    9%
    		+91%
    Seizure —
    2%
    2%
    6%
    		+169%
    Thought Loops
    5%
    2%
    2%
    		— -61%
    Appetite Suppression
    5%
    2%
    		— — -69%

    Positive Effects

    Effect Light (n=41) Common (n=130) Strong (n=104) Heavy (n=96) Change
    Music Enhancement
    51%
    52%
    42%
    35%
    		-30%
    Stimulation
    34%
    38%
    19%
    18%
    		-48%
    Euphoria
    37%
    36%
    34%
    31%
    		-14%
    Color Enhancement
    24%
    31%
    33%
    34%
    		+40%
    Empathy
    32%
    22%
    32%
    23%
    		-27%
    Tactile Enhancement
    29%
    25%
    20%
    17%
    		-43%
    Focus Enhancement
    22%
    23%
    24%
    21%
    		-5%
    Introspection
    22%
    13%
    20%
    9%
    		-57%
    Body High
    10%
    11%
    7%
    3%
    		-68%
    Creativity Enhancement
    10%
    2%
    6%
    3%
    		-68%
    Pain Relief —
    4%
    		— — 0%

    Dosage Distribution

    Dose distribution from experience reports

    Median: 420.0 mg IQR: 272.0–670.0 mg n=397

    Real-World Dose Distribution

    62K Doses

    From 1037 individual dose entries

    Oral (n=790)

    Median: 358.5mg 25th: 236.0mg 75th: 600.0mg 90th: 831.0mg
    mg/kg median: 5.45 mg/kg 75th: 8.956

    Insufflated (n=6)

    Median: 200.0mg 25th: 200.0mg 75th: 350.0mg 90th: 550.0mg
    mg/kg median: 2.596 mg/kg 75th: 5.077

    Common Combinations

    Most co-occurring substances in experience reports

    Form / Preparation

    Most common forms and preparations reported

    Body-Weight Dosing

    Dose relative to body weight from reports with weight data

    Median: 6.0 mg/kg IQR: 3.856–9.153 mg/kg n=389

    Redose Patterns

    Redosing behavior across 610 reports

    11.1% Redosed
    1.2 Avg Doses
    78m Median Interval
    Read full reports on Erowid →

    Legal Status

    Country Status Notes
    Australia Pharmacy 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.
    Austria Unscheduled (Pharmacy Only) Not listed in the Suchtmittelgesetz (Federal Law on Narcotics). Sales restricted to pharmacies but preparations are available without prescription.
    Belgium OTC Available over-the-counter without prescription and without age restriction. DXM-only products available at some pharmacies.
    Brazil OTC DXM-containing products sold over-the-counter without prescription.
    Canada Exempt 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.
    China Psychotropic Drug Class II Classified as a Class II psychotropic substance effective July 1, 2024. Single-ingredient DXM medications restricted to hospital sales. Combination products containing DXM with other active ingredients such as guaifenesin remain available over-the-counter.
    Czech Republic Mixed (Formulation Dependent) Some pharmacies require prescription for tablet formulations while liquid preparations may be available without prescription.
    Denmark Prescription Type A The DXM-containing product Dexofan is classified as a prescription type A medication, requiring a doctor's prescription for purchase.
    Egypt Controlled (Dose Dependent) Products containing more than 10 mg per dose are controlled and require a prescription. Combination products with lower DXM content may be available over-the-counter.
    Estonia Prohibited/Restricted Among the few countries where DXM-containing antitussive preparations face significant restrictions beyond standard pharmacy controls.
    Finland Pharmacy 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.
    France Behind Counter (No Prescription) Available at pharmacies without a prescription but kept behind the counter rather than on open shelves.
    Germany Unscheduled (Pharmacy Only) Not listed in the Betäubungsmittelgesetz (Federal Law on Narcotics). Sales restricted to pharmacies but available without prescription in syrup and tablet forms.
    Hong Kong Pharmacy 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.
    Hungary Mixed (Formulation Dependent) Cough syrups containing DXM available over-the-counter. Pure DXM capsules require a prescription.
    Iran OTC DXM-only and DXM combination products available over-the-counter without prescription.
    Israel OTC Available in popular over-the-counter cough medicines without prescription.
    Japan Legal (OTC) DXM is legal and has been available in various retail settings. Historically sold in specialized shops.
    Latvia Prohibited/Restricted Among the few countries where DXM-containing antitussive preparations face significant restrictions beyond standard pharmacy controls.
    Malaysia Controlled Medication Classified as a controlled medication available from pharmacies and clinics. Recreational use is explicitly prohibited under law.
    Mexico Uncontrolled 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.
    Netherlands Pharmacy Only (Restricted) As of January 1, 2011, no longer available over-the-counter outside of pharmacies. Pharmacies are required to record buyer identification information.
    New Zealand OTC Available over-the-counter without identification requirements. Products including Robitussin Dry Cough Forte widely available.
    Poland OTC (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.
    Romania Mixed (Formulation Dependent) Pure DXM preparations require a prescription. Liquid formulations and products marketed as Tussin are available over-the-counter, though enforcement varies.
    Russia Schedule III Listed as a Schedule III controlled substance following government anti-DXM campaigns. Subject to tighter restrictions than in most other countries.
    Singapore Class A Prescription Drug Classified as a Class A prescription medication. Cannot be purchased without a valid prescription from a physician.
    South Korea Controlled (with exemptions) Listed as a controlled psychotropic substance. However, combination products meeting specific requirements are exempt from control if the single dose contains 7.5-15 mg and daily usage does not exceed 60 mg.
    Sweden Controlled (Narcotics Class V) Classified as a controlled narcotic substance. The cough medicine Tussidyl containing DXM was withdrawn from Swedish sales in 1999 due to abuse concerns and associated risks. No longer marketed in Sweden.
    Switzerland Abgabekategorie 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.
    Thailand Behind Counter Available behind the pharmacy counter. A prescription is obtained from the dispensing pharmacist at point of sale.
    Turkey Prescription Only DXM-only products require a prescription for purchase. Availability may be limited.
    United Kingdom Pharmacy Only Medication Specifically exempted from control under the Misuse of Drugs Act 1971 and 2001. 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.
    United States Unscheduled (OTC) Specifically excluded from the Controlled Substances Act of 1970. Sold over-the-counter and regulated by the FDA when sold for human consumption. Many states and retailers require purchasers to be 18 or older. California enacted legislation effective January 1, 2012 prohibiting sales to minors without prescription. Illinois passed legislation effective January 1, 2007 restricting sales to FDA-compliant over-the-counter formulations. New York prohibited sales to those under 18 as of September 2013. Selling pure powder has resulted in convictions for selling misbranded drugs.

    Harm Reduction

    drugs.wiki

    DXM polistirex is an extended‑release resin complex; its slower, flatter absorption commonly produces a weaker peak with a much longer tail than DXM HBr. Because come‑up may take 1–3 hours, premature redosing can stack exposures and lead to unexpectedly long, dysphoric, or anxious trips; wait at least 4–6 hours before considering any additional dosing and avoid it entirely with ER products. CYP2D6 genetics and inhibitors strongly change exposure: poor metabolizers (≈9%) can have ~8× higher bioavailability and ~8× longer half‑life than extensive metabolizers, producing unusually prolonged effects and higher toxicity risk; potent CYP2D6 inhibitors (quinidine, fluoxetine, paroxetine, bupropion) can mimic PM status. Avoid combination OTCs: acetaminophen (hepatotoxicity above ~3–4 g/day), first‑gen antihistamines (anticholinergic delirium; QT), doxylamine/diphenhydramine (delirium/seizure risk), guaifenesin (severe nausea/vomiting), and decongestants (cardiovascular strain). Mixing with serotonergic antidepressants (SSRIs/SNRIs/MAOIs), tramadol, linezolid, St. John’s wort, or MDMA increases serotonin‑toxicity risk (agitation, hyperthermia, clonus, diaphoresis)—seek emergency care if these occur. Do not attempt to defeat the polistirex coating (e.g., crushing/acid tricks or crude ‘extractions’); release becomes unpredictable and may not convert to free DXM. Expect impaired coordination and judgment for the rest of the day and often into the next morning—do not drive, swim, or perform hazardous tasks for at least 12–24 hours after significant doses. Many syrups contain sorbitol and other excipients that can cause GI upset, dehydration, and electrolyte loss—sip oral fluids with electrolytes and avoid heavy physical exertion. Start low if on any psychiatric medication or with a history of psychosis, bipolar disorder, seizure disorder, significant hypertension, or liver disease; dissociatives can precipitate mania/psychosis and increase BP/HR. Space use 2–4 weeks or longer to manage tolerance and reduce compulsive patterns; frequent redosing increases adverse mental health outcomes. Always read the exact product label: ER bottles often state ‘dextromethorphan polistirex equivalent to 30 mg DXM HBr per 5 mL’; this is a labeling equivalence for cough dosing, not a guarantee of equal recreational effect. If severe agitation, hyperthermia, rigid muscles, confusion, or seizures occur, this may signal serotonin toxicity or severe overdose—seek urgent medical help and avoid anticholinergic sedatives unless directed by a clinician.

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