|Summary sheet: Gabapentin|
|Common names||Gabapentin, Neurontin, Gabarone, Gralise|
|Systematic name||1-(Aminomethyl)cyclohexaneacetic acid|
|Routes of Administration|
Gabapentin (also known as Neurontin) is a depressant substance of the gabapentinoid class which is used as an anticonvulsant, analgesic and anxiolytic. It was originally developed to treat epilepsy and is currently used to relieve neuropathic pain and restless leg syndrome. It is recommended as a first line agent for the treatment of neuropathic pain arising from diabetic neuropathy, post-herpetic neuralgia, and central neuropathic pain.
Gabapentin is also an effective tool for treating social anxiety disorder, panic disorder and generalized anxiety disorder. It is these effects which provide gabapentin with some recreational potential in a manner that can be accurately compared to a mild benzodiazepine. However, these recreational effects diminish very quickly with repeated usage and are most commonly reported by those who do not have a tolerance to this compound.
The bioavailability of gabapentin is relatively low and is inversely proportional to the dose. This means that higher doses have lower biovailability than lower doses. The bioavailability of gabapentin is approximately 60%, 47%, 34%, 33%, and 27% following 900, 1200, 2400, 3600, and 4800 mg/day Gabapentin has minimal hydrophilicity, with saturation values of up to 4490mg/L of pure water. It is instead mostly lipophilic, making unsaturated fats such as vegetable oil and olive oil significantly boost the total amount of absorption. This means that eating a high fat meal substantially increases gabapentin's bioavailability, due to the fact that unsaturated fats bind to gabapentin to allow for absorption, and that meals slow down and thus increase gabapentin absorption by decreasing gabapentin transporter saturation.
Gabapentin transporter saturation occurs when large enough doses of gabapentin are consumed in a short enough period of time to result in the body being unable to absorb any more gabapentin, causing a significant reduction in bioavailability, which largely accounts for the drop in bioavailability seen with increasing doses. Due to a lack of available unsaturated gabapentin transporters, this results in an inability of transporters to carry gabapentin, resulting in large amounts of gabapentin passing through the digestive system without being used by one's body.
This effect can easily be significantly lessened by taking lower doses more often instead of higher doses less frequently. As a general rule for most individuals, using any more than 250-300mg of gabapentin every 30-40 minutes will result in wasting a significant portion of the total dose of gabapentin, although this number varies depending on the individual. Alkaline environments inhibit absorption of gabapentin, so lowering the pH of one's stomach using acidic substances such as soda/pop will boost bioavailability as well. It is generally not recommended to take antacids 2 hours before or after taking gabapentin, because although not dangerous, it will severely lower the total absorption of gabapentin.
- 1 Chemistry
- 2 Pharmacology
- 3 Subjective effects
- 4 Toxicity and harm potential
- 5 Legal status
- 6 See also
- 7 External links
- 8 References
Gabapentin, or 1-(aminomethyl)cyclohexanacetic acid, is an analogue of the neurotransmitter GABA. It contains a cyclohexane ring bound to a methylamino chain CH3NH2. At the same location, R1, the cyclohexane ring is also substituted with an acetic acid group. Gabapentin is structurally analagous to GABA. GABA contains an amino group bound to the terminal carbon of a butanoic acid chain. The structure of gabapentin contains the secondary carbon R3 of the butanoic acid chain in GABA incorporated into an attached cyclohexane ring, converting it into a tertiary carbon while still maintaining the chain.
Gabapentin modulates the action of glutamate decarboxylase (GAD) and branched chain aminotransferase (BCAT), two enzymes involved in GABA biosynthesis. In human and rat studies, gabapentin was found to increase GABA biosynthesis, and to increase non-synaptic GABA neurotransmission in vitro. As the GABA system is the most prolific inhibitory receptor set within the brain, its increase in biosynthesis results in the sedating and anxiolytic (or calming effects) of gabapentin on the nervous system.
Gabapentin, as a gabapentinoid, has also been shown to bind to the α2δ-1 subunit of Voltage-Gated Calcium Channels to act as a VGCC blocker, which contributes to its inhibitory, analgesic, and anxiolytic effects. It is uncertain exactly how this method of action contributes to gabapentin's psychoactive effects.
The effects listed below are based upon the subjective effects index and personal experiences of PsychonautWiki contributors. These 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 of inducing a full range of effects. Likewise, adverse effects become much more likely on higher doses and may include serious injury or death.
- Sedation - Gabapentin is mildly sedating and can produce a lethargic state. At higher doses it may lead to a moderate sedated state.
- Appetite enhancement - This effect is not particularly prominent, but is reported to occur in some people. It can have a synergistic effect when combined with cannabis.
- Muscle relaxation - While this effect is generally less powerful than that of benzodiazepines, it is still prevalent.
- Physical euphoria
- Decreased libido - Many users note a marked decrease in their sex drive when taking gabapentin. This can happen when it is taken both recreationally or medically.
- Perception of bodily lightness - At very high doses, some users report feeling lighter.
- Dizziness - This effect is particularly prevalent at higher doses. It should be noted that the dizziness experienced on gabapentin is not always considered overly unpleasant and many users may not necessarily mind it.
- Seizure suppression - Gabapentin is commonly used as an anticonvulsant. It is often combined with other anticonvulsants when used to treat epilepsy and other seizure disorders.
- Pain relief - Gabapentin is used to control pain, particularly fibromyalgic/neuropathic pain (nerve pain) and restless leg syndrome. It is generally considered to be not very effective for the management of acute pain, such as opiates.
- Muscle twitching
- Motor control loss
- Analysis suppression
- Anxiety suppression
- Dream potentiation
- Thought deceleration
- Cognitive euphoria
- Emotion suppression
- Depersonalization and Derealization - At very high doses, gabapentin can induce a mild dissociative state.
- Amnesia - Gabapentin induces a substantially lower amount of amnesia compared to other GABAergic drugs such as benzodiazepines.
- Suicidal ideation
- Internal hallucination - At higher doses, some users report mild to strong closed eye visuals. These can include, but are not limited to psychedelic-like geometry and landscapes. It has been noted that smoking cannabis greatly potentiates these effects.
- Visual disconnection - This effect is generally quite mild and appears inconsistently at very high doses. It results in feeling as if one's sense of vision is distant or vague and being viewed through a screen or window. However, it is not capable of higher levels of visual disconnection that produce holes, spaces and voids or hallucinatory structures in the same way that traditional dissociatives can.
Anecdotal reports which describe the effects of this compound within our experience index include:
- Experience:1.2 g gabapentin, alcohol, and half of 150 mg Effexor XR - Pretty lovely for socializing and giggles
- Experience:7500mg - Analysis of gabapentin
- Experience:A combination of tramadol, clonazepam, gabapentin, and dimenhydrinate
Toxicity and harm potential
GABApentin has a low toxicity relative to dose. The most common side effects of gabapentin in adult patients include dizziness, fatigue, drowsiness, weight gain, and peripheral edema (swelling of extremities). Gabapentin may also produce sexual dysfunction in some patients whose symptoms of which may include loss of libido, inability to reach orgasm, and erectile dysfunction. Gabapentin should be used carefully in patients with renal impairment due to possible accumulation and toxicity.
It is strongly recommended that one use harm reduction practices when using this drug.
In 2009, the U.S. Food and Drug Administration issued a warning of an increased risk of depression and suicidal thoughts and behaviors in patients taking gabapentin (along with other anticonvulsant drugs), modifying the packaging insert to reflect this. A 2010 meta analysis confirmed the increased risk of suicide associated with gabapentin use.
People who accidentally or intentionally overdose may experience drowsiness, sedation, blurred vision, slurred speech, somnolence and possibly death (if a very high amount was taken and particularly if combined with alcohol). Serum gabapentin concentrations may be measured to confirm diagnosis.
Tolerance and addiction potential
Gabapentin is not considered psychologically addictive. However, it is possible to develop a physical dependence on the drug. In fact, people can experience withdrawal symptoms for up to 45 days after they stop taking gabapentin. Although gabapentin does give some people a euphoric “high” which can cause abuse, gabapentin abusers do not present with the kind of compulsive, drug-seeking behavior or strong cravings associated with other more common depressants such as opioids, alcohol or benzodiazepines.
Tolerance will develop to the anxiolytic effects with prolonged continous usage. After cessation, the tolerance returns to baseline in 7-14 days. Withdrawal symptoms or rebound symptoms may occur after ceasing usage abruptly following a few weeks or longer of steady dosing, and may necessitate a gradual dose reduction.
- Opioids - Combining opioids with gabapentin can cause death from respiratory failure.
- GABAergic depressants - Gabapentin significantly potentiates the effects of alcohol, benzodiazepines and other GABAgenics which may lead to blackouts, and dangerous behaviour.
This legality section is a stub.
As such, it may contain incomplete or wrong information. You can help by expanding it.
Gabapentin is a prescription only medicine and can only be prescribed following a consultation with a doctor.
- United States: Gabapentin is not a scheduled substance but may only be sold with prescription.
- Kentucky: Gabapentin became a Schedule 5 controlled substance in March 2017.
- Restless legs syndrome: clinical presentation diagnosis and treatment | http://www.sleep-journal.com/article/S1389-9457(15)00647-4/abstract
- EFNS guidelines on the pharmacological treatment of neuropathic pain: 2010 revision (PubMed.gov / NCBI) | https://www.ncbi.nlm.nih.gov/pubmed/20402746
- The role of anticonvulsant drugs in anxiety disorders: a critical review of the evidence (PubMed.gov / NCBI) | https://www.ncbi.nlm.nih.gov/pubmed/17502773
- Manual of Clinical Psychopharmacology | https://books.google.co.uk/books?id=D3zz1NCm3qcC&pg=PA345&hl=en
- Successful Psychopharmacology: Evidence-Based Treatment Solutions for Achieving Remission | https://books.google.co.uk/books?id=dnAlO_Veu2QC&pg=PA124&hl=en
- Neurontin Clinical Pharmacology Biopharmaceutics Review | http://www.accessdata.fda.gov/drugsatfda_docs/nda/2002/21-397.pdf_Neurontin_BioPharmr.pdf
- Gabapentin data sheet | http://reference.medscape.com/drug/neurontin-gralise-gabapentin-343011#showall
- Mechanisms of action of gabapentin (PubMed.gov / NCBI) | http://www.ncbi.nlm.nih.gov/pubmed/9686247
- Anticonvulsant medications and the risk of suicide, attempted suicide, or violent death. | https://www.ncbi.nlm.nih.gov/pubmed/20388896/
- R.C. Baselt, Disposition of Toxic Drugs and Chemicals in Man, 8th edition, Biomedical Publications, Foster City, CA, 2008, pp. 677–8. ISBN 978-0-9626523-7-0.