Gabapentin clinical efficacy

Muscas GC, Chiroli S, Luceri F, Mastio MD, Balestrieri F, Arnetoli G. Conversion from thrice daily to twice daily administration of gabapentin (GBP) in partial epilepsy analysis of clinical efficacy and plasma levels. Seizure 2000 9(l) 47-50. 

Ramsay RE. Clinical efficacy and safety of gabapentin. Neurology 1994 44 523-32. 

Amyotrophic lateral sclerosis is currently treated with riluzole, which improves survival in 30% of patients. Riluzole, an NMDA receptor antagonist, is discussed later in this chapter. A clinical trial of gabapentin, a (y aminobutyric acid (GABA) agonist, in amyotrophic lateral sclerosis demonstrated little efficacy. Antioxidants have also not demonstrated significant efficacy so far. 

Pregabalin is another second-generation anticonvulsant that has recently obtained FDA approval for treatment of neurogenic pain, and several randomized placebo controlled studies have shown that this compound is efficacious in the treatment of painful diabetic neuropathy [32]. Doses between 300 and 600 mg/day have shown effect already apparent after 1 week of treatment. There are few clinically important drug interactions as there is no interference with the cytochrome 450 system. This compound requires minimal dose titration and seems easy to use. Side effects to gabapentin and pregabalin include drowsiness, dizziness and peripheral edema. 

While there are ample studies to confirm the efficacy of gabapentin and pregabalin, there is a dearth of comparisons with established antidepressant drugs such as amitriptyline and other tricyclics. Other concerns include the possible ability of gabapentin to cause neuropathy, so reassurance would be welcome that the benefits outweigh the risks in differing clinical 293 circumstances, particularly in the long term. 

Post-herpetic neuralgia (PHN) gabapentin therapy may be initiated as a single 300-mg dose on day 1,600 mg/day on day 2 (divided BID), and 900 mg/day on day 3 (divided TID). The dose can subsequently be titrated up as needed for pain relief up to a target daily dose of 1800 mg (divided TID). In clinical studies, efficacy was also demonstrated over a range of doses... 

Sandercock D, Cramer M, Wu J, Chiang YK, Biton V, Heritier M. Gabapentin extended release for the treatment of painful diabetic peripheral neuropathy efficacy and tolerability in a double-blind, randomized, controlled clinical trial. Diabetes Care 2009 32(2) e20. 

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