|Common names||Memantine, Memaxa, Ebixa, Namenda, Namenda XR, Namzaric (with donepezil, both extended-release)|
|Routes of Administration|
|Summary sheet: Memantine|
Memantine is a dissociative substance of the adamantane class that produces long-lived dissociative effects when administered. It is a derivative of amantadine and is pharmacologically related to compounds like PCP, ketamine, and DXM, although its recreational use is comparatively rare.
Memantine was first synthesized by Eli Lilly and Company in 1968 as a potential agent to treat diabetes.
Memantine is classified as an NMDA receptor antagonist. This means it binds to and blocks the signaling of excitatory receptors in the central nervous system. These compounds induce a state known as "dissociative-anesthesia," which has a number of hallucinogenic attributes.
In medicine, memantine is used primarily in humans in the treatment of neurodegenerative diseases like Alzheimer's disease. It also has seen use as a nootropic for its cognitive-enhancing effects.
- 1 Chemistry
- 2 Pharmacology
- 3 Subjective effects
- 4 Toxicity and harm potential
- 5 Legal status
- 6 See also
- 7 External links
- 8 Literature
- 9 References
Memantine, or 3,5-dimethyladamantan-1-amine, is a man-made molecule classified as a substituted adamantane derivative. Its core structure is adamantane, a diamondoid of four interlocked cyclohexane rings in a stable 3-dimensional lattice conformation. Memantine is substituted with a methyl carbon at both R3 and R5; it contains an amine substitution at R1. Its name is derived from its structure; 3,5-dimethyladamantan-1-amine.
Glutamatergic (NMDA receptor)
Memantine is a moderate-affinity voltage-dependent uncompetitive antagonist at glutamatergic NMDA receptors. NMDA receptors allow for electrical signals to pass between neurons in the brain and spinal column; for the signals to pass, the receptor must be open. Dissociatives close the NMDA receptors by blocking them. This disconnection of neurons leads to loss of feeling, difficulty moving, and eventually the famous “hole”.
Memantine is distinct from most other dissociatives due to its fast, voltage-dependent binding kinetics that allow for functional ionic transmission through the NMDA receptors unless in the presence of a large enough concentration of agonists, causing memantine to be more similar in pharmacodynamical profile at the NMDA receptor to endogenous magnesium than to other dissociatives. Memantine's unique pharmacological profile allows it to elicit neuroprotective properties at doses that lack strong amounts of impairment, making it useful in the treatment of neurodegenerative disorders.
Serotonergic (5-HT3 receptor)
Memantine acts as a non-competitive antagonist at the 5-HT3 receptor, with a potency similar to that for the NMDA receptor.
Cholinergic (nicotinic acetylcholine receptor)
Memantine acts as a non-competitive antagonist at different neuronal nicotinic acetylcholine receptors (nAChRs) at potencies possibly similar to the NMDA and 5-HT3 receptors, but this is difficult to ascertain with accuracy because of the rapid desensitization of nAChR responses. Alpha-7 nAChR upregulates quickly in response to antagonism, which could explain the cognitive-enhancing effects of chronic memantine treatment.
Dopaminergic (D2 receptor)
Memantine acts as an agonist at the dopamine D2 receptor with equal or slightly higher affinity than to the NMDA receptors.
Sigmaergic (σ1 receptor)
It acts as an agonist at the σ1 receptor with a low Ki of 2.6 µM. The effects of this activity are unclear (as the role of sigma receptors, in general, is not yet that well understood) and memantine is probably too weak at the sigma binding site to exhibit significant agonist effects, only exhibiting partial agonism or antagonism.
The effects listed below are based upon the subjective effects index and personal experiences of PsychonautWiki contributors. The listed effects should be taken with a grain of salt and will rarely (if ever) occur all at once, but heavier doses will increase the chances and are more likely to induce a full range of effects. Likewise, adverse effects become much more likely on higher doses and may include serious injury or death.
Memantine is more stimulating than ketamine or MXE but less so than PCP and its derivatives.
- Stimulation - Memantine is mildly stimulating in comparison to other dissociatives such as ketamine, MXE, or DCK.
- Spontaneous physical sensations - The memantine "body high" is a sharp, pleasurable tingling sensation which has a location specific to the hands, feet, and head.
- Cough suppression
- Decreased libido
- Increased heart rate
- Nausea - High doses of memantine can sometimes result in nausea and vomiting.
- Perception of decreased weight - This creates the sensation that the body is floating and has become entirely weightless. This effect is oddly stimulating and encourages physical activities at low to moderate dosages by making the body feel light and effortless to move.
- Physical autonomy
- Physical euphoria - This results in feelings which range from mild pleasure to powerful, all-encompassing bliss.
- Tactile suppression - This partially to entirely suppresses one's own sense of touch, creating feelings of numbness within the extremities. It is responsible for the anesthetic properties of this substance.
- Motor control loss - A loss of gross and fine motor control alongside of balance and coordination is prevalent within memantine and becomes especially strong at higher dosages. This means that one should be sitting down before the onset unless they are experienced in case of falling over and injuring oneself.
- Double vision - This component is prevalent at moderate to heavy doses and makes reading impossible unless the user closes one eye.
- Frame rate suppression
- Pattern recognition suppression - This effect generally occurs at higher doses and makes the user unable to recognize and interpret perceivable visual data.
- Visual acuity suppression - In other words, this effect is the blurring or muddling of vision.
The visual geometry produced by memantine can be described as dark but sharp when compared to that of ketamine or DXM. It is unknown to what level the geometry memantine extends to. Memantine can be described as simplistic in complexity, abstract in style, synthetic in feel, structured in organization, dimly lit in lighting, multicoloured in scheme, flat in shading, soft in edges, both small and large in size, slow in speed, smooth in motion, equal in rounded and angular corners, immersive, in-depth, and progressive in intensity.
The cognitive effects of memantine is said to be more clear-headed but less euphoric when compared to ketamine or MXE.
- Anxiety suppression
- Cognitive euphoria
- Conceptual thinking
- Creativity enhancement
- Dream suppression
- Feelings of impending doom
- Immersion enhancement
- Information processing suppression
- Memory suppression
- Thought deceleration
- Time distortion
- Tactile disconnection
- Visual disconnection - This eventually results in memantine's equivalent to the ketamine "k-hole" or, more specifically, holes, spaces and voids alongside structures. However, many users may find it difficult or at least uncomfortable to reach this state due to the high dose required and associated side effects.
- Consciousness disconnection
Toxicity and harm potential
The toxicity and long-term health effects of recreational memantine use do not seem to have been studied in any scientific context and the exact toxic dosage is unknown, although up to 400mg has been tolerated. This is because memantine has very little history of recreational human usage.
Anecdotal evidence from people who have tried memantine within the community suggests that there do not seem to be any negative health effects attributed to simply trying this drug at low to moderate doses by itself and using it sparingly (but nothing can be completely guaranteed). Independent research should always be done to ensure that a combination of two or more substances is safe before consumption.
Tolerance and addiction potential
The dependence potential for memantine is unknown. However, due to its long duration and long onset, users are discouraged to redose, meaning it is unlikely users will develop an addiction.
Memantine has very limited information on drug combinations and should therefore be treated with extreme caution when combined with other drugs.
Although many psychoactive substances are safe on their own, they can become dangerous and even life-threatening when combined with other substances. The list below contains some common potentially dangerous combinations, but may not include all of them. Certain combinations may be safe in low doses of each but still increase the potential risk of death. Independent research should always be done to ensure that a combination of two or more substances is safe before consumption.
- Stimulants - This combination can potentiate the anxiety-inducing, manic, delusional and disinhibiting aspects of dissociatives, particularly those without pronounced motor and consciousness-suppression components like ketamine as this can increase the likelihood of a panic event or psychotic episode.
- Prominent examples include PCP and its analogs 3-MeO-PCP, MXE, and the diarylethylamine dissociatives like diphenidine or ephenidine. There is also evidence that suggests that combining these two increases their neurotoxicity. Anecdotally, worsened comedowns are also commonly reported when these two classes of substances are combined.
- Depressants - Because both depress the respiratory system, this combination can result in an increased risk of suddenly falling unconscious, vomiting and choking to death from the resulting suffocation. If nausea or vomiting occurs, users should attempt to fall asleep in the recovery position or have a friend move them into it.
- 25x-NBOMe - Both the NBOMe series and this compound induce powerful stimulation and their interaction may cause severe side effects. These can include thought loops, seizures, increased blood pressure, vasoconstriction, increased heart rate, and heart failure (in extreme cases).
- Alcohol - It is dangerous to combine alcohol, a depressant, with stimulants due to the risk of excessive intoxication. Stimulants decrease the sedative effect of alcohol which is the main factor most people consider when determining their level of intoxication. Once the stimulant wears off, the effects of alcohol will be significantly increased, leading to intensified disinhibition as well as respiratory depression. If combined, one should strictly limit themselves to only drinking a certain amount of alcohol per hour.
- DXM - This combination may cause increased heart rate and panic attacks.
- MXE - Increased heart rate and blood pressure may occur.
- Tramadol - This combination can increase the risk of seizures.
- Nicotine - Anecdotal reports suggest an interaction between tobacco and memantine.
- Opioids - Memantine is reported to increase the effects, prevent build up and in some cases reverse tolerance to opioids.
- Stimulants - Memantine is reported to increase the effects, prevent build up and in some cases reverse tolerance to stimulants.
- Alcohol - Memantine is reported to increase the effects, prevent build up and, in some cases, reverse tolerance to alcohol.
This legality section is a stub.
As such, it may contain incomplete or wrong information. You can help by expanding it.
- Australia: Memantine is S4, meaning it is available only with a prescription.
- United Kingdom: Memantine is a POM (prescription-only medicine).
- United States: Memantine is only available through a prescription.
- Lipton, S. A. (2006). Paradigm shift in neuroprotection by NMDA receptor blockade: Memantine and beyond. Nature Reviews Drug Discovery, 5(2), 160. https://doi.org/10.1038/nrd1958
- Morris, H., & Wallach, J. (2014). From PCP to MXE: A comprehensive review of the non-medical use of dissociative drugs. Drug Testing and Analysis, 6(7–8), 614–632. https://doi.org/10.1002/dta.1620
- Parsons, C. G., Rammes, G., & Danysz, W. (2008). Pharmacodynamics of memantine: an update. Current neuropharmacology, 6(1), 55-78. - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2645549/?report=classic