NationMaster - Encyclopedia: Gabapentin

Gabapentin (brand name Neurontin) is a medication originally developed for the treatment of epilepsy. Presently, gabapentin is widely used to relieve pain, especially neuropathic pain. Gabapentin is well tolerated in most patients, has a relatively mild side-effect profile, and passes through the body unmetabolized. In pharmacology and toxicology, a route of administration is the path by which a drug, fluid, poison or other substance is brought into contact with the body. ... Neuropathy is a disease of the peripheral nervous system. ...

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. Its exact mechanism of action is unknown, but its therapeutic action on neuropathic pain is thought to involve voltage-gated N-type calcium ion channels. It is thought to bind to the α2δ subunit of the voltage-dependent calcium channel in the central nervous system. Chemical structure refers to the spatial arrangement of atoms in a molecule and the chemical bonds that hold the atoms together. ... Chemical structure of D-aspartic acid, a common amino acid neurotransmitter. ... Gamma-aminobutyric acid (usually abbreviated to GABA) is an inhibitory neurotransmitter found in the nervous systems of widely divergent species. ... Wikipedia does not yet have an article with this exact name. ... Ion channels are present in the membranes that surround all biological cells. ... This article needs to be cleaned up to conform to a higher standard of quality. ... A diagram showing the CNS: 1. ...

Clinical uses

Gabapentin was originally approved in the U.S. by the Food and Drug Administration (FDA) in 1994 for use as an adjunctive medication to control partial seizures (effective when added to other antiseizure drugs). In 2002, approval was added for treating postherpetic neuralgia (neuropathic pain following shingles, other painful neuropathies, and nerve related pain).^[2] â€œFDAâ€ redirects here. ... It has been suggested that this article or section be merged with Focal seizures. ... Postherpetic neuralgia (PHN) is a painful condition caused by the varicella zoster virus in a dermatomal distribution (the area governed by a particular sensory nerve) after an attack of herpes zoster (HZ) (commonly known as shingles), usually manifesting after the vesicles have crusted over and begun to heal. ...

Although not "indicated" (i.e., not FDA-approved), gabapentin has been found to be effective in prevention of frequent migraine headaches,^[3] neuropathic pain^[4] and nystagmus.^[5] Migraine is a form of headache, usually very intense and disabling. ... Neuropathy is usually short for peripheral neuropathy, meaning a disease of the peripheral nervous system. ... Nystagmus is involuntary eye movement that can be part of the vestibulo-ocular reflex (VOR), with the eyes moving first in the direction of the lesioned side (slow phase) followed by a quick correction (fast phase) to the opposite side or away from the lesioned side. ...

Gabapentin has also been used in the treatment of bipolar disorder. However, its off-label use for this purpose is increasingly controversial.^[6] Some claim gabapentin acts as a mood stabilizer and has the advantage of having fewer side-effects than more conventional bipolar drugs such as lithium and valproic acid. Some small, non-controlled studies in the 1990s, most sponsored by gabapentin's manufacturer, suggested that gabapentin treatment for bipolar disorder may be promising.^[6] However, more recently, several larger, controlled, and double-blind studies have found that gabapentin was no more effective than (and in one study, slightly less effective than) placebo.^[7] Despite this scientific evidence that gabapentin in the treatment of bipolar disorder is not an optimal treatment, many psychiatrists continue to prescribe it for this purpose. For other uses, see Bipolar. ... The term off-label refers to the use of a drug for a medical condition other than for which it was officially approved and marketed. ... A mood stabilizer is a psychiatric medication used to treat mood disorders characterized by rapid and unstable mood shifts. ... This article is about the chemical element named Lithium. ... Valproic acid (VPA) is a chemical compound that has found clinical use as an anticonvulsant and mood-stabilizing drug, primarily in the treatment of epilepsy and bipolar disorder. ... For the band, see 1990s (band). ...

Gabapentin has limited usefulness in the treatment of anxiety disorders such as social anxiety disorder and obsessive-compulsive disorder, in treatment-resistant depression, and for insomnia.^[8]^[9] Gabapentin may be effective in reducing pain and spasticity in multiple sclerosis.^[6] Anxiety is a physiological state characterized by cognitive, somatic, emotional, and behavioral components (Seligman, Walker & Rosenhan, 2001). ... Social anxiety, sometimes known as social phobia or social anxiety disorder (SAD), is a common form of anxiety disorder that causes sufferers to experience intense anxiety in some or all of the social interactions and public events of everyday life. ... Clinical depression (also called major depressive disorder, or unipolar depression when compared to bipolar disorder) is a state of intense sadness, melancholia or despair that has advanced to the point of being disruptive to an individuals social functioning and/or activities of daily living. ... This article is about the sleeping disorder. ...

Gabapentin has also been found to help patients with post-operative chronic pain (usually caused by nerves that have been severed accidentally in an operation and when grown back, have reconnected incorrectly). Symptoms of this include a tingling sensation near or around the area where the operation was performed, sharp shooting pains, severe aches after much movement, constant 'low ache' all day and sometimes a general 'weak' feeling. These symptoms can appear many months after an operation, and therefore the condition can go unnoticed.

Gabapentin is also prescribed to patients being treated with anti-androgenic compounds to reduce the incidence and intensity of the accompanying hot flushes.^[10]

Gabapentin (administered orally) is one of two medications (the other being flumazenil, which is administered intravenously) used in the expensive Prometa Treatment Protocol for methamphetamine, cocaine and alcohol addiction. Gabapentin is administered at a dosage of 1200 mg taken at bedtime for 40–60 days. Though the combination of flumazenil infusions and gabapentin tablets is a licensed treatment, there is no prohibition against a physician prescribing gabapentin outside the Prometa protocol. There have been reports by methamphetamine addicts that gabapentin alone in doses of 1200 mg at bedtime taken for 40–60 days has been effective in reducing the withdrawal symptoms and almost eliminating cravings or desire to use methamphetamine.^{[citation needed]} Flumazenil (flumazepil, AnexateÂ®, LanexatÂ®, MaziconÂ®, RomaziconÂ®) is a benzodiazepine antagonist, used as an antidote in the treatment of benzodiazepine overdose. ... Prometa is an integrated, physician-based treatment protocol for alcohol or methamphetamine dependence. ...

Gabapentin has occasionally been prescribed for treatment of idiopathic subjective tinnitus, but a double blind, randomized controlled trial found it ineffective.^[11] Tinnitus (IPA pronunciation: or ,[1] from the Latin word for ringing[2]) is the perception of sound in the human ear in the absence of corresponding external sound(s). ... The Double blind method is an important part of the scientific method, used to prevent research outcomes from being influenced by the placebo effect or observer bias. ... A randomized controlled trial (RCT) is a form of clinical trial, or scientific procedure used in the testing of the efficacy of medicines or medical procedures. ... In health care, including medicine, a clinical trial (synonyms: clinical studies, research protocols, medical research) is a process in which a medicine or other medical treatment is tested for its safety and effectiveness, often in comparison to existing treatments. ...

Marketing of gabapentin

Gabapentin is best known under the brand name Neurontin manufactured by Pfizer subsidiary Parke-Davis. A Pfizer subsidiary named Greenstone markets generic Gabapentin. Pfizer Incorporated (NYSE: PFE) is the worlds largest research-based pharmaceutical company[1].[1] The company is based in New York City. ... Parke-Davis was a pharmaceutical company which was previously a subsidiary of Warner-Lambert prior to Warner-Lamberts acquisition by Pfizer in 2000. ... Pfizer Incorporated (NYSE: PFE) is the worlds largest research-based pharmaceutical company[1].[1] The company is based in New York City. ...

In December 2004, the FDA granted final approval to a generic equivalent to Neurontin made by Israeli firm Teva. Teva Pharmaceutical Industries Ltd. ...

Neurontin is one of Pfizer’s best selling drugs, and was one of the 50 most prescribed drugs in the United States in 2003. However, in recent years Pfizer has come under heavy criticism for its marketing of Neurontin, facing allegations that behind the scenes Parke-Davis marketed the drug for at least a dozen supposed uses for which the drug had not been FDA approved. This article does not cite any references or sources. ... Parke-Davis was a pharmaceutical company which was previously a subsidiary of Warner-Lambert prior to Warner-Lamberts acquisition by Pfizer in 2000. ... A whistleblower is someone in an organization who witnesses behavior by members that is either contrary to the mission of the organization, or threatening to the public interest, and who decides to speak out publicly about it. ...

By some estimates, so-called off-label prescriptions account for roughly 90% of Neurontin sales.^[12] While off-label prescriptions are common for a number of drugs and are perfectly legal (if not always appropriate), marketing of off-label uses of a drug is strictly illegal.^[13] In 2004, Warner-Lambert agreed to plead guilty and pay $430 million in fines to settle civil and criminal charges regarding the illegal marketing of Neurontin for off-label purposes, and further legal action is pending. The courts of New York State, for example, have refused to certify a class of injured parties who took Neurontin for off-label use, finding that they had failed to state that they had had any injury.^[14] Off-label use is the practice of prescribing drugs for a purpose outside the scope of the drugs approved label, most often concerning the drugs indication. ... Year 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ...

The University of California, San Francisco (UCSF) has archived ^[15] and studied ^[16] the documents made public by this case which opens a unique window into pharmaceutical marketing and illegal drug promotion. However, Pfizer maintains that the illegal activity originated in 1996, well before it accquired Parke-Davis (through its acquisition of Warner-Lambert) in 2000. Several lawsuits are underway after people prescribed gabapentin for off-label treatment of bipolar disorder attempted or committed suicide. UCSF in 1908, with the streetcar that used to run on Parnassus Avenue The University of California, San Francisco (UCSF) is one of the worlds leading centers of health sciences research, patient care, and education. ... Year 1996 (MCMXCVI) was a leap year starting on Monday (link will display full 1996 Gregorian calendar). ... Parke-Davis was a pharmaceutical company which was previously a subsidiary of Warner-Lambert prior to Warner-Lamberts acquisition by Pfizer in 2000. ... Pfizer, Incorporated (NYSE: PFE), is a global pharmaceutical company based in New York City. ... Year 2000 (MM) was a leap year starting on Saturday (link will display full 2000 Gregorian calendar). ... For other uses, see Suicide (disambiguation). ...

Pfizer has developed a successor to gabapentin, called pregabalin (being marketed as Lyrica). Structurally related to gabapentin, pregabalin is effective for neuropathic pain associated with diabetes, fibromyalgia, and shingles, as well as for the treatment of epilepsy and seizures. Pregabalin (brand name: LyricaÂ®) is a new anticonvulsant drug indicated as an add on therapy for partial onset seizures and for certain types of neuropathic pain. ... Fibromyalgia (FM or FMS) is a chronic syndrome (constellation of signs and symptoms) characterized by diffuse or specific muscle, joint, or bone pain, fatigue, and a wide range of other symptoms. ...

Side effects

Gabapentin's most common side effects in adult patients include dizziness, drowsiness, and peripheral edema (swelling of extremities)^[17]; these mainly occur at higher doses, in the elderly. Children 3–12 years of age were also observed to be susceptible to mild-to-moderate mood swings, hostility, concentration problems, and hyperactivity. An increase in formation of adenocarcinomas was observed in rats during preclinical trials, however the clinical significance of these results remains undetermined. Although rare, there are several cases of hepatotoxicity reported in the literature.^[18] Gabapentin should be used carefully in patients with renal impairment due to possible accumulation and toxicity.^[19]^[20] Gabapentin has an iGuard risk rating of Orange^[21] (elevated risk). Peripheral edema ... Adenocarcinoma is a form of carcinoma that originates in glandular tissue. ... Hepatotoxicity (from hepatic toxicity) implies chemical-driven liver damage. ... iGuard is the holding company for iGuard. ...

Abuse potential

Though gabapentin is not a controlled substance, it does produce psychoactive effects that could lead to abuse of the drug. However, it is widely regarded as having little or no abuse potential. Pregabalin, a gabapentinoid with higher potency marketed for neuropathic pain, is a controlled substance, under the DEA Schedule V. Pregabalin (brand name: LyricaÂ®) is a new anticonvulsant drug indicated as an add on therapy for partial onset seizures and for certain types of neuropathic pain. ... The Controlled Substances Act (CSA), Title II of the Comprehensive Drug Abuse Prevention and Control Act of 1970, is the legal foundation of the United States governments fight against the abuse of drugs and other substances. ...

References

^ BNF (March 2003) 45
^ Pfizer: Product Monograph Neurontin®PDF (251 KiB) Retrieved 14 August 2006
^ Mathew, NT; Rapoport A, Saper J, Magnus L, Klapper J, Ramadan N, Stacey B, Tepper S (2001). "Efficacy of gabapentin in migraine prophylaxis". Headache 41 (2): 119–28. ISSN 0017-8748. PMID 11251695. Retrieved on 2006-08-14.
^ Backonja, MM; Serra J (2004). "Pharmacologic management part 1: better-studied neuropathic pain diseases". Pain Med 5 (Suppl 1): S28–47. ISSN 1526-2375. PMID 14996228.
^ Choudhuri, I; Sarvananthan N, Gottlob I (May 26, 2006). "Survey of management of acquired nystagmus in the United Kingdom". Eye. ISSN 0950-222X. PMID 16732211.
^ ^a ^b ^c Mack, Alicia (2003). "Examination of the evidence for off-label use of gabapentin" (PDF). Journal of Managed Care Pharmacy 9 (6): 559–68. Retrieved on 2006-08-14.
^ Pande, AC; Crockatt JG, Janney CA, Werth JL, Tsaroucha G. (2000). "Gabapentin in bipolar disorder: a placebo-controlled trial of adjunctive therapy" (Abstract). Bipolar Disorders 2 (3 Pt 2): 249–55. PMID 11249802. Retrieved on 2006-08-14.
^ Chouinard, G (May 2006). "The search for new off-label indications for antidepressant, antianxiety, antipsychotic and anticonvulsant drugs". J Psychiatry Neurosci 31 (3): 168–176. ISSN 1180-4882. PMID 16699602.
^ Frye, Mark A.; et al (2000). "A Placebo-Controlled Study of Lamotrigine and Gabapentin Monotherapy in Refractory Mood Disorders" (Abstract). Journal of Clinical Psychopharmacology 20 (6): 607–14. Retrieved on 2006-08-14.
^ Guttuso, T Jr; Kurlan R; McDermott MP; Kieburtz K (Feb 2003). "Gabapentin's effects on hot flashes in postmenopausal women: a randomized controlled trial". Obstet Gynecol 101 (2): 337–45. Retrieved on 2007-02-15.
^ Piccirillo, JF; Finnell J, Vlahiotis A, Chole RA, Spitznagel E (2007). "Relief of idiopathic subjective tinnitus: is gabapentin effective?". Arch Otolaryngol Head Neck Surg 133 (4): 390–7. PMID 17438255. Retrieved on 2007-07-22.
^ "Huge penalty in drug fraud, Pfizer settles felony case in Neurontin off-label promotion.", San Francisco Chronicle, 2004-05-14, p. C-1.
^ Jane E. Henney, MD (2006). "Editorial: Safeguarding Patient Welfare: Who's In Charge?". Annals of Internal Medicine 145 (4): 305-307. Retrieved on 2006-08-14.
^ http://www.courts.state.ny.us/reporter/3dseries/2007/2007_05813.htm Baron v. Pfizer, Inc., 2007 N.Y. Slip Op. 05813 (App. N.Y., July 5, 2007)]
^ http://dida.library.ucsf.edu
^ http://www.annals.org/cgi/content/full/145/4/284
^ FDA approved labeling for Neurontin capsules, tablets, and oral solution. (February 2005). Note that an updated labeling has been approved, but is not available online as of November 2006
^ Maria C Lasso-de-la-Vega Pharm.D (2001). "Gabapentin-associated hepatotoxicity" (Abstract). Am J Gastroenterol 96 (12): 3460–3462. Retrieved on 2007-02-14.
^ Ayhan DOGUKAN (2006). "Gabapentin-induced coma in a patient with renal failure" (Abstract). Hemodialysis International 10 (2): 168–169. Retrieved on 2007-02-14.
^ Bookwalter T, Gitlin M (2005). "Gabapentin-induced neurologic toxicities" (Abstract). Pharmacotherapy 25 (12): 1817–9. PMID 16305301. Retrieved on 2007-02-14.
^ http://www.iguard.org/drugs/NEURONTIN.html

Otherwise known as the doctors prescribing Bible the British National Formulary (BNF) contains a wide spectrum of information on prescribing and pharmacology, among others indications, side effects and costs of the prescription of all medication drugs available on the National Health Service. ... â€œPDFâ€ redirects here. ... A kibibyte (a contraction of kilo binary byte) is a unit of information or computer storage, commonly abbreviated KiB (never kiB). 1 kibibyte = 210 bytes = 1,024 bytes The kibibyte is closely related to the kilobyte, which can be used either as a synonym for kibibyte or to refer to... ISSN, or International Standard Serial Number, is the unique eight-digit number applied to a periodical publication including electronic serials. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 226th day of the year (227th in leap years) in the Gregorian calendar. ... ISSN, or International Standard Serial Number, is the unique eight-digit number applied to a periodical publication including electronic serials. ... ISSN, or International Standard Serial Number, is the unique eight-digit number applied to a periodical publication including electronic serials. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 226th day of the year (227th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 226th day of the year (227th in leap years) in the Gregorian calendar. ... ISSN, or International Standard Serial Number, is the unique eight-digit number applied to a periodical publication including electronic serials. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 226th day of the year (227th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st Century. ... is the 46th day of the year in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st Century. ... is the 203rd day of the year (204th in leap years) in the Gregorian calendar. ... Year 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ... May 14 is the 134th day of the year (135th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 226th day of the year (227th in leap years) in the Gregorian calendar. ... February 2005 : â† - January - February - March - April - May - June - July - August - September - October - November - December - â†’ Pope John Paul II is taken to a hospital suffering from a serious case of influenza. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st Century. ... is the 45th day of the year in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st Century. ... is the 45th day of the year in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st Century. ... is the 45th day of the year in the Gregorian calendar. ...

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Categories: All articles with unsourced statements | Articles with unsourced statements since July 2007 | Anticonvulsants | Mood stabilizers There are several sulphonamide-based groups of drugs. ... Acetazolamide, sold under the trade name DiamoxÂ®, is a carbonic anhydrase inhibitor that is used to treat glaucoma, epileptic seizures, benign intracranial hypertension and altitude sickness. ... Ethoxzolamide (6-ethoxybenzothiazole-2-sulfonamide, alternatively known as Ethoxyzolamide) is a sulfonamide medication that functions as a carbonic anhydrase inhibitor. ... Sultiame (rINN, also known as sulthiame) is a sulfonamide and inhibitor of the enzyme carbonic anhydrase. ... Zonisamide (brand name ZonegranÂ®) is an anticonvulsant used as an adjunctive therapy in adults with partial-onset seizures. ... The propionate (also propanoate) ion is C2H5COOâˆ’ (propionic acid minus one hydrogen ion). ... Beclamide (marketed as Chloracon, Hibicon, Posedrine, Nydrane, Seclar, and other names) is a propionate and was used as a sedative and as an anticonvulsant. ... An aldehyde. ... Paraldehyde is the cyclic form of three acetaldehyde molecules (a trimer). ... A bromide is a phrase, or person who uses phrases, which have been used and repeated so many times as to become either insincere in their meaning, or seem like an attempt at trying to explain the obvious. ... Potassium bromide (KBr) is a salt, used as an anticonvulsant and a sedative in the 1800s. ... Sodium bromide is the chemical compound with the formula NaBr. ...

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