Gabapentin

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Summary sheet: Gabapentin


Gabapentin
Gabapentin.svg
Chemical Nomenclature
Common names Gabapentin, Neurontin, Gabarone, Gralise
Substitutive name Gabapentin
Systematic name 1-(Aminomethyl)cyclohexaneacetic acid
Class Membership
Psychoactive class Depressant
Chemical class Gabapentinoid
Routes of Administration

WARNING: Always start with lower doses due to differences between individual body weight, tolerance, metabolism, and personal sensitivity. See responsible use section.



Oral
Dosage
Bioavailability 27% - 60%[citation needed]
Threshold 200 mg
Light 200 - 600 mg
Common 600 - 900 mg
Strong 900 - 1200 mg
Heavy 1200 mg +
Duration
Total 5 - 8 hours
Onset 30 - 90 minutes









DISCLAIMER: PW's dosage information is gathered from users and resources for educational purposes only. It is not a recommendation and should be verified with other sources for accuracy.

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.[1] 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.[2]

Gabapentin is also an effective tool for treating social anxiety disorder, panic disorder[3][4] and generalized anxiety disorder.[5][6] 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 with repeated usage and are most commonly reported by those who try this compound who do not have a tolerance.

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[7] Eating a high fat meal substantially increases gabapentin's bioavailability.[8]

Chemistry

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.

Pharmacology

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.[9] As the GABA system is the most prolific inhibitory receptor set within the brain, its modulation results in the sedating (or calming effects) of gabapentin on the nervous system.

Gabapentin has also been shown to bind to the α2δ-1 subunit of voltage-gated calcium ion channels which contributes to its analgesic effects. It is uncertain how this contributes to gabapentin's psychoactive effects.

Subjective 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.

Physical effects
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Cognitive effects
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Visual effects
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Experience reports

Anecdotal reports which describe the effects of this compound within our experience index include:


Toxicity and harm potential

This document, provided with prescription gabapentin, contains detailed information regarding its 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).[11] 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.[12][13] Gabapentin should be used carefully in patients with renal impairment due to possible accumulation and toxicity.[14]

It is strongly recommended that one use harm reduction practices when using this drug.

Suicide

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),[15] modifying the packaging insert to reflect this. A 2010 meta analysis confirmed the increased risk of suicide associated with gabapentin use.[16]

Lethal dosage

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.[17]

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.

Dangerous interactions

Legal status

Handcuffs-300px.png

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.[citation needed]

  • United States: Gabapentin is not a scheduled substance but may only be sold with prescription.[citation needed]
    • Kentucky: Gabapentin became a Schedule 5 controlled substance in March 2017.[citation needed]

See also

External links

References

  1. Restless legs syndrome: clinical presentation diagnosis and treatment | http://www.sleep-journal.com/article/S1389-9457(15)00647-4/abstract
  2. EFNS guidelines on the pharmacological treatment of neuropathic pain: 2010 revision (PubMed.gov / NCBI) | https://www.ncbi.nlm.nih.gov/pubmed/20402746
  3. 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
  4. Manual of Clinical Psychopharmacology | https://books.google.co.uk/books?id=D3zz1NCm3qcC&pg=PA345&hl=en
  5. Successful Psychopharmacology: Evidence-Based Treatment Solutions for Achieving Remission | https://books.google.co.uk/books?id=dnAlO_Veu2QC&pg=PA124&hl=en
  6. https://books.google.co.uk/books?id=82oiYYHGNTQC&pg=PA765&hl=en
  7. Neurontin Clinical Pharmacology Biopharmaceutics Review | http://www.accessdata.fda.gov/drugsatfda_docs/nda/2002/21-397.pdf_Neurontin_BioPharmr.pdf
  8. Gabapentin data sheet | http://reference.medscape.com/drug/neurontin-gralise-gabapentin-343011#showall
  9. Mechanisms of action of gabapentin (PubMed.gov / NCBI) | http://www.ncbi.nlm.nih.gov/pubmed/9686247
  10. Anticonvulsant medications and the risk of suicide, attempted suicide, or violent death. | https://www.ncbi.nlm.nih.gov/pubmed/20388896/
  11. http://www.accessdata.fda.gov/drugsatfda_docs/label/2009/020235s041,020882s028,021129s027lbl.pdf
  12. https://books.google.co.uk/books?id=jTc3AAAAQBAJ&pg=PA137&hl=en
  13. https://books.google.co.uk/books?id=_VzzAgAAQBAJ&pg=PT482&hl=en
  14. http://www.accessdata.fda.gov/drugsatfda_docs/label/2014/020235s057,020882s041,021129s039lbl.pdf
  15. http://www.fda.gov/Drugs/DrugSafety/PostmarketDrugSafetyInformationforPatientsandProviders/ucm100190.htm
  16. https://www.ncbi.nlm.nih.gov/pubmed/20388896
  17. 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.