Gabapentin anticonvulsant

K, Alder, F, Smith, A, McKernan, R, Metters, K, O Neill, GP, Facaille, JC and Hebert TE (2001) y-Aminobutyric acid type B receptors with specific heterodimer composition and postsynaptic actions in hippocampal neurons are targets of anticonvulsant gabapentin action. Mol. Pharmacol. 59 144-152. 

Gabapentin (Neurontin). Another anticonvulsant, gabapentin, is unique among psychiatric medications in that, like lithium, it is not metabolized by the liver but... 

Anhut H, Leppik I, Schmidt B, Thomann P. Drug interaction study of the new anticonvulsant gabapentin with phen3rtoin in epileptic patients. Naunyn Schmiedebergs Arch Pharmacol (1988) 337 (Suppl), R127. 

Anticonvulsants Carbamazepine, valproic acid, gabapentin, topiramate... 

Other anticonvulsants, such as gabapentin and topiramate, are also being used by some clinicians, but controlled trials are lacking. 

Agents Acetaminophen or NSAID combinations with opioids Adjuncts Tricyclic antidepressants Anticonvulsants Radiopharmaceuticals (Bone pain) Acetamnophen (See above) Opioids Titrate Amitriptyline 10-50 mg Imipramine 10-50 mg NSAIDs (See above) Gabapentin (Neurontin) 3.6 g... 

Anticonvulsants. Finally, several antiseizure medications have been tried. These include valproic acid (Depakote, Depakene), carbamazepine (Tegretol), Lamotrig-ine (Lamictal), and gabapentin (Neurontin). The anticonvulsants are effective treatments for bipolar disorder. Their use for major depression needs to be studied further. Please refer to Section 3.4 Bipolar Disorders. 

Anticonvulsants. Several antiseizure medicines have been studied in the treatment of PTSD, and some results have been encouraging. Open label studies, first with carbamazepine (800-1200 mg/day) and later with valproate (500-2000 mg/ day), demonstrated overall improvement in PTSD patients, though not for intrusive recollections per se. Recent open label studies of gabapentin, lamotrigine, tiagabine, and topiramate have suggested these anticonvulsants might also be helpful for some PTSD symptoms. 

Other anticonvulsants snch as oxcarbazepine, gabapentin, and lamotrigine may also be helpful in treating the affective lability and impulsivity seen in BPD, though little data is available. Each of these medications is discussed in Chapter 3. 

Carbamazepine, phenytoin, pheno-barbital, and other anticonvulsants (except for gabapentin) induce hepatic enzymes responsible for drug biotransformation. Combinations between anticonvulsants or with other drugs may result in clinically important interactions (plasma level monitoring ). 

If gabapentin is discontinued or an alternate anticonvulsant medication is added to the therapy, this should be done gradually over a minimum of 1 week. 

Pharmacology Gabapentin is an oral antiepileptic agent. The mechanism by which it exerts its anticonvulsant and analgesic actions is unknown. 

Bertrand S et al. The anticonvulsant, antihyperalgesic agent gabapentin is an agonist at brain gamma-aminobutyric acid type B receptors negatively coupled to voltage-dependent calcium channels. J Pharmacol Exper Therap 2001 298 15-24. 

Gabapentin is used in combination with other anticonvulsant agents in the management of partial seizures (Bruni, 1998) with or without secondary generalization (Morris, 1999). A few (McElroy et al., 1997 Knoll et ah, 1998), but not all (Dimond et al., 1996), preliminary reports suggested that gabapentin may have an-timanic efficacy in adults with BD. 

Gabapentin does not bind to plasma proteins, is not appreciably metabolized, nor induces hepatic enzyme activity (AHFS, 2000) Consequently, it does not appear to alter the pharmacokinetics of commonly used anticonvulsant drugs or oral contraceptives (Ketter et al.,... 

These data suggest that there is more available information for use of lithium than for other mood stabilizers, and that adolescents hospitalized with adolescent-onset, acute mania have rates of response between 50% and 80%. Supplementation with sedating medication appears to be common but not systematically evaluated. Children hospitalized with mania also respond to lithium, but their comorbid disorders often need separate attention. Open trials with DVP in hospitalized adolescents are also supported. There is much less information on CBZ and there are no data on newer anticonvulsants such as lamotrigine, topiramate, or gabapentin. These data are largely consistent with data from studies of hospitalized adults with classic mania. 

More recently, gabapentin has been added to the arsenal of medications used for the treatment of chronic pain, along with other anticonvulsant drugs, such as carbamazepine and clonazepam, as used in the treatment of neuropathies in children (Berde et ah, 1993 Green and Kowalik 1994). 

Virtually all anticonvulsants are or have been of interest for the treatment of bipolar disorder. However, the importance of controlled data cannot be understated. For example, gabapentin, an anticonvulsant that initially received much attention as a potential mood stabilizer, was compared with placebo and did not appear to stabilize mood (Frye et al. 2000 Pande et al. 2000). Similar negative results were seen with topiramate in placebo-controlled trials for the treatment of mania. Although these medications might be useful adjuncts in some patients, given the currently expanded pharmacopoeia of medications with positive controlled trial data in bipolar disorder, we do not recommend the primary use of agents that have only case reports as an evidence base or controlled studies with predominantly negative results. 

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