Gabapentin


 * Gabapentin** (brand names **Fanatrex**, **Gabarone**, **Gralise**, **Neurontin**, **Nupentin**) is a pharmaceutical drug, specifically a [|GABA] [|analogue] . It was originally developed for the treatment of [|epilepsy], and currently is also used to relieve [|neuropathic pain].

Gabapentin provides significant pain relief in about a third of people who take it for [|fibromyalgia] or chronic [|neuropathic pain]. [|[3]] It is also effective in reducing [|narcotic] usage post operatively [|[4]] and is helpful in neuropathic pain due to [|cancer]. [|[5]] It has not been shown to be useful for [|HIV] associated sensory neuropathy. [|[6]] When used for neuropathic pain it does not appear superior to [|carbamazepine]. [|[7]] Further evidence is needed to determine if it is effective for [|migraine] prevention. [|[8]] It appears to be equally effective as [|pregabalin] and is of lower cost. [|[9]] It does not appear to be of benefit in treating [|complex regional pain syndrome]. [|[10]]

Seizures
Gabapentin is approved for treatment of [|focal seizures] in a number of countries [|[11]] and evidence supports its use for treating [|partial] and [|mixed seizure] disorders however there is insufficient evidence for its use in [|generalized epilepsy]. [|[12]] There is little data to support its initial use over older [|anticonvulsant] medication for any type of seizure disorder. [|[13]]

Other
There is some evidence of benefit in [|acquired pendular nystagmus] and [|infantile nystagmus] but not in [|periodic alternating nystagmus]. [|[14]] [|[15]] Gabapentin may help with [|menopausal] symptoms. [|[16]] [|[17]] It may be effective in reducing pain and spasticity in [|multiple sclerosis]. [|[18]] Gabapentin has been used to treat some symptoms of opiate withdrawal, [|[19]] but tests for [|smoking cessation] treatment have had mixed results. [|[20]] [|[21]]

Negative
Gabapentin has been prescribed in the mental health context. Numerous trials show that it is not effective alone as a [|mood-stabilizing] treatment for [|bipolar disorder] and so has no therapeutic advantage in having fewer side-effects over better established bipolar drugs such as [|lithium] and [|valproic acid]. Gabapentin is useful in the treatment of [|anxiety] associated with bipolar disorder, but has limited usefulness in disorders such as [|social anxiety disorder] and [|obsessive-compulsive disorder], in treatment-resistant [|depression] , and for [|insomnia]. [|[22]] [|[23]] A [|double blind], [|randomized controlled] [|trial] found gabapentin ineffective for the treatment of idiopathic subjective [|tinnitus]. [|[24]]

Adverse effects
Gabapentin's most common side effects in adult patients include dizziness, fatigue, weight gain, drowsiness, and [|peripheral edema] (swelling of extremities); [|[25]] these mainly occur at higher doses in the elderly. Also, children 3–12 years of age were observed to be susceptible to mild-to-moderate mood swings, hostility, concentration problems, and hyperactivity. Although rare, there are several cases of [|hepatotoxicity] reported in the literature. [|[26]] [|[27]] Gabapentin should be used carefully in patients with [|renal impairment] due to possible accumulation and toxicity. [|[28]] [|[29]] An increase in formation of [|adenocarcinomas] was observed in rats during preclinical trials; however, the clinical significance of these results remains undetermined. Gabapentin is also known to induce pancreatic acinar cell carcinomas in rats through an unknown mechanism, perhaps by stimulation of DNA synthesis; these tumors did not affect the lifespan of the rats and did not [|metastasize]. [|[30]]

Suicide
Gabapentin has been associated with an increased risk of suicidal acts or violent deaths. [|[31]] 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 [|[32]] modifying the [|packaging insert] to reflect this. [|[25]] In July 2009, the manufacturer of gabapentin ( [|Pfizer] ) went to trial regarding the association between gabapentin and the increased risk of suicide. [|[33]]

[ [|edit] ] Withdrawal
Gabapentin should not be discontinued abruptly after long term use. Abrupt or over rapid withdrawal may provoke a withdrawal syndrome reminiscent to [|alcohol] or [|benzodiazepine withdrawal]. [|[34]] [|[35]] Gradual reduction over a period of weeks or months helps minimize or prevents the withdrawal syndrome. [|[34]] Side effects upon discontinuation of gabapentin that have been reported in medical literature include [|insomnia], [|restlessness] , [|agitation] , [|anxiety] , [|disorientation] , [|confusion] , [|light sensitivity] , [|diaphoresis] , [|headaches] , [|palpitations] , [|hypertension] , [|chest pain] , and [|flu-like symptoms]. [|[34]] [|[36]] [|[37]] [|[38]] In at least one case, abrupt cessation of a high dose of gabapentin triggered a [|seizure] in an individual with no history of [|epilepsy]. [|[37]]

Overdosage
Persons who accidentally or intentionally ingested overdoses have manifested drowsiness, blurred vision, slurred speech and [|somnolence] or coma. Serum gabapentin concentrations may be measured to confirm diagnosis. [|[39]]

Pharmacology
Gabapentin was initially synthesized to mimic the [|chemical structure] of the [|neurotransmitter] gamma-aminobutyric acid (GABA), but is not believed to act on the same brain receptors. The mechanism of action that leads to its rapid [|analgesic] effect is simply unknown. Some of its activity may involve interaction with [|voltage-gated calcium channels]. Gabapentin binds to the α2δ subunit ( [|1] and [|2] ) and has been found to reduce calcium currents after chronic but not acute application via an effect on trafficking [|[40]] of voltage-dependent calcium channels in the [|central nervous system]. [|[41]] Another possible [|mechanism of action], reported by Ben Barres and colleagues in // [|Cell] // in 2009, is that gabapentin halts the formation of new synapses. [|[42]]

Related drugs
[|Parke-Davis] developed a drug called [|pregabalin] to be a successor of gabapentin. [|[43]] Pregabalin was brought to market by Pfizer as [|Lyrica] after the company acquired Warner-Lambert. Pregabalin is related in structure to gabapentin and is approved for treatment of epilepsy, neuropathic pain associated with diabetes, [|fibromyalgia], [|post-herpetic neuralgia] , and [|generalized anxiety disorder]. Compared to gabapentin, pregabalin is more potent, absorbs faster and has greater bioavailability. Higher potency means that less of the medication is required for the same effect. This does not necessarily result in fewer side effects. [|[44]] [|[45]] Another new drug [|atagabalin] has been trialled by Pfizer as a treatment for [|insomnia]. [|[46]] One must remain skeptical of industry run trials [|[47]] as, despite significant monetary damages awarded in trials discussed below, there is no certainty the company is not still suppressing negative or equivocal data and news reports indicate this may be the case with [|pregabalin] as well. [|[48]]

Gabapentin is also known as Fanatrex, Gabarone, Gralise, Neurontin, and Nupentin It is a pharmaceutical drug, specifically a GABA analogue It was originally developed for the treatmet of epilepsy and currently is used to relieve neuropathic pain Gabapentin is used primarlily for the treatment of seizures, neuropathic pain, and hot flashes There are however concerns regarding the quality of the research on its use to treat migraines, bipolar disorders and pain Gabapentin has been associated with an increased risk of suicidal acts or violent deaths. In 2009 the FDA issued a warning of an increased risk of depression and suicidal thoughts and behaviors in patients taking Gabapetin