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Memantine
3,5-Dimethyl-1-aminoadamantane
Namenda, Ebixa, Axura, Memaxa, Namenda XR
Memantine is an adamantane derivative and NMDA receptor antagonist primarily prescribed for the management of moderate-to-severe Alzheimer's disease.citation needed It works by blocking glutamate-mediated neuronal excitotoxicity, distinguishing it mechanistically from the cholinesterase inhibitors typically used in Alzheimer's treatment.12 At supratherapeutic doses, memantine can produce prolonged dissociative effects reportedly lasting 16 or more hours, placing it among the longest-duration dissociatives available.
Dosage & Duration
Subjective Effects
Legacy content. A statistically backed ontology from Mindstate Design Labs is coming soon.
Memantine is an NMDA receptor antagonist whose subjective profile is fundamentally dissociative, though its character is far removed from faster-acting dissociatives. Even therapeutic doses have been found to produce mild dissociative-like effects, while supratherapeutic doses can bring on a prolonged dissociative 'hole' lasting up to 16 or more hours. Notably, it appears to lack the euphoria associated with many recreational substances, and its extremely long duration makes recreational use uncommon.
Physical
The body experience is dominated by CNS depression, including dizziness, drowsiness, sedation, lethargy, and slurred speech, with heavier exposures capable of progressing to loss of consciousness.
Sedation
Cognitive
The headspace is marked by dissociation, confusion, and disorientation, sometimes accompanied by anxiety or agitation. Because NMDA antagonism interferes with the synaptic plasticity underlying learning and memory, higher doses can impair memory formation.
Disorienting
Visual
Hallucinatory States
Reported in a subset of users rather than as a consistent effect.
See also: Dissociative Intensity Scale, Subjective Effects of Dissociatives
Pharmacology
Pharmacodynamics
Memantine acts as an uncompetitive antagonist of the NMDA receptor, binding within the open ion channel to block pathological calcium influx driven by excessive glutamate signaling.citation needed It displays preferential inhibition of extrasynaptic NMDA receptors, while its low affinity and rapid off-rate kinetics allow normal synaptic NMDA function to be preserved during physiological glutamate release.56 Beyond its primary mechanism, memantine acts as a non-competitive antagonist at 5-HT3 receptors with potency similar to its NMDA activitycitation needed and as an antagonist at α7 nicotinic acetylcholine receptors.6 It has additionally been reported to act as an agonist at dopamine D2High receptors7 and as a weak agonist at sigma-1 receptors.
Pharmacokinetics
Memantine has an oral bioavailability of approximately 100%4 and reaches peak plasma levels within 3 to 7 hours.8 It undergoes negligible metabolism by cytochrome P450 enzymes,8 producing three minor metabolites that retain minimal NMDA receptor antagonist activity.citation needed The drug is eliminated primarily through renal excretion, with 57 to 82% appearing unchanged in urine.9 Its elimination half-life ranges from 60 to 80 hours,8 and renal clearance is dependent on urinary pH, with more alkaline urine slowing elimination.8
Caution
Use cautionThese 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.
AbacavirAbrocitinibAcebutololAceclofenacAcemetacin
Tolerance
Tolerance timelines are rules of thumb, not exact schedules, and vary widely between individuals and use patterns.
Cross Tolerance
Other NMDA receptor antagonists
Harm Potential
Addiction & Dependence
Psychological
Extremely LowRecreational use is rare due to the drug's very long duration of action (>40 hours) and apparent lack of euphoric effects. Misuse potential is considered limited compared to other NMDA receptor antagonists.citation needed
Toxicity
Cardiovascular
Blood clots and heart failure have been reported as severe but rare adverse effects, primarily documented in clinical use among elderly patients with dementia.citation needed
Urinary System
Cystitis has been reported as a less common adverse effect in clinical settings.
Psychosis Risk
Psychosis is listed as a severe but rare side effect.citation needed Hallucinations and confusion are more common adverse effects (≥1% of patients) in clinical populations.10 At supratherapeutic recreational doses, dissociative effects may produce psychotomimetic symptoms.
History & Culture
Discovery and Development
Memantine was first synthesized and patented by Eli Lilly and Company in 1963, originally developed as a potential anti-diabetic agent.citation needed However, the compound proved ineffective at lowering blood sugar and the project stalled. Nearly a decade later, in 1972, researchers discovered…
Trip Reports
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Legality
By Country
Prescription8
DenmarkPrescription onlyBekendtgørelse om recepter og dosisdispensering af lægemidler (BEK nr. 827 af 24/06/2024), § 6; Lægemiddelstyrelsens Medicinpriser product record for Memantin "Accord" (varenummer 158045)1415
The Danish Medicines Agency's current Medicinpriser record identifies memantine as the active substance in Memantin "Accord" and assigns the product to dispensing group A. Under § 6 of Denmark's prescription order, group A is a prescription-only dispensing group and medicines in it may ordinarily be dispensed only once on the same prescription.
European UnionPrescription only
GermanyPrescription onlyArzneimittelverschreibungsverordnung (AMVV) official BfArM list of substances and preparations18
Memantine appears in the official BfArM list associated with prescription-only status.
NetherlandsPrescription onlyMemantine is a prescription-only medicine in the Netherlands. The CBG medicines database classifies the authorised Memantine CF product, containing memantine hydrochloride corresponding to memantine, as available exclusively by prescription; the Geneesmiddelenwet defines a UR medicine as one that may be supplied only on prescription.
SwitzerlandPrescription onlySwissmedic authorisation no. 65181 (supply category B)21
Swissmedic's current professional information for Memantin-Mepha Teva identifies memantine hydrochloride as the active ingredient and lists the authorized packages in supply category B. Swissmedic defines category B as dispensing on a medical or veterinary prescription.
United KingdomPrescription onlyMemantine is available in the United Kingdom only on prescription. The current UK product information for Memantine 20 mg film-coated tablets identifies the legal category as prescription-only medicine, and regulation 214 of the Human Medicines Regulations 2012 prohibits sale or supply of a prescription-only medicine except in accordance with an appropriate practitioner's prescription, subject to statutory exemptions.
References
Source Pages
Bluelight: Memantine higher dose discussion- Bluelight: Memantine megathread
DrugBank
Erowid Experience: A Few Words of Caution (exp32398)- Erowid Experience: Being Disconnected From Reality (exp109789)
- Erowid Experience: Useful But Not Recreational (exp108837)
- Erowid: Memantine Vault
PsychonautWiki: Memantine
Wikipedia
Citations
- Memantine — StatPearls. NCBI Bookshelf / StatPearls Publishing (n.d.). https://www.ncbi.nlm.nih.gov/books/NBK500025/1
- Memantine and Cholinesterase Inhibitors: Complementary Mechanisms in the Treatment of Alzheimer's Disease. (2013). https://pmc.ncbi.nlm.nih.gov/articles/PMC3753463/1
- Shahrina Alam, Kaelyn Skye Lingenfelter, Aaron M. Bender, & Craig W. Lindsley. (September 2017). Classics in Chemical Neuroscience: Memantine. ACS Chemical Neuroscience, 8(9), 1823–1829. https://doi.org/10.1021/acschemneuro.7b0027012
- Ebixa 10 mg film-coated tablets Summary of Product Characteristics (SmPC). (emc) (13 December 2021). https://www.medicines.org.uk/emc/product/8222/smpc12
- Memantine preferentially blocks extrasynaptic over synaptic NMDA receptor currents in hippocampal autapses. The Journal of Neuroscience, 30(33), 11246–11250 (August 2010). https://doi.org/10.1523/jneurosci.2488-10.20101
- Pharmacodynamics of Memantine: An Update. Current Neuropharmacology (n.d.). https://pmc.ncbi.nlm.nih.gov/articles/PMC2645549/12
- Memantine agonist action at dopamine D2High receptors. Synapse, 62(2), 149–153 (February 2008). https://doi.org/10.1002/syn.204721
- NAMENDA (memantine hydrochloride) Tablets — Prescribing Information. DailyMed (n.d.). https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=bc6e059d-1951-4fa3-b904-230d4165724d1234
- Namenda (Memantine) for Moderate-to-Severe Alzheimer's Disease — Pharmacotherapy Update. Cleveland Clinic (n.d.). https://www.clevelandclinicmeded.com/medicalpubs/pharmacy/mayjune2004/namenda.htm1
- Namenda- memantine hydrochloride tablet; Namenda- memantine hydrochloride kit. DailyMed (1 November 2018). https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=b9f27baf-aa2a-443a-9ef5-e002d23407ba1234
Further Reading
Clinical review (PMC2762361)
Drugs.com – Alcohol interaction- Drugs.com – Ketamine + Memantine interaction
- Memantine misuse and social networks: Reddit analysis (PMC)
- Memantine vs Ketamine NMDAR study
Nervewing: Ether + Memantine- Pharmacokinetics of memantine (PMC6822834)
Reddit: r/ResearchChemicals - 500mg trip report
Article Status
Step 1 · Automated synthesisAn autonomous workflow built by Josie Kins compiled this article's foundation from information published across the web.
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A first pass manual review and edit of article prose and copy has been performed by subject-matter expert Lyrea. This does not guarantee factual accuracy. An additional human review for each of this article's citations is yet to be performed.
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Recent changes7 human edits · latest
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24 January 2026
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
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