Gabapentin Action of Mechanism


The chemical structure of gabapentin (Neurontin) is derived by addition of a cyclohexyl group to the backbone of gamma-aminobutyric acid (GABA).

Gabapentin (Generic Neurontin ) is used to help control partial seizures (convulsions) in the treatment of epilepsy. This medicine cannot cure epilepsy and will only work to control seizures for as long as you continue to take it.

Gabapentin (Generic Neurontin ) is also used to manage a condition called postherpetic neuralgia, which is pain that occurs after shingles. It’s also taken for nerve pain. Nerve pain can be caused by different illnesses, including diabetes and shingles, or it can happen after an injury.

Gabapentin (Generic Neurontin ) works in the brain to prevent seizures and relieve pain for certain conditions in the nervous system. It is not used for routine pain caused by minor injuries or arthritis. Gabapentin is an anticonvulsant.

Occasionally, gabapentin (Generic Neurontin ) is used to prevent migraine headaches. Gabapentin (Neurontin) and pregabalin (Lyrica) are anticonvulsants and nerve pain medicines which have structural similarities to the inhibitory neurotransmitter GABA.

Gabapentin (Generic Neurontin ) is available only with your doctor’s prescription.

Gabapentin (Generic Neurontin ) is available in the following dosage forms:
Capsule
Tablet
Tablet, Extended Release, 24 HR
Solution
Suspension

DOSAGE FORMS AND STRENGTHS of Gabapentin
Capsules
100 mg: white hard gelatin capsules printed with “PD” on the body and300 mg: yellow hard gelatin capsules printed with “PD” on the body and “Neurontin/300 mg” on the cap
400 mg: orange hard gelatin capsules printed with “PD” on the body and “Neurontin/400 mg” on the cap
Tablets
600 mg: white elliptical film-coated scored tablets debossed with “NT” and “16” on one side
Gabapentin 800 mg: white elliptical film-coated scored tablets debossed with “NT” and “26” on one side
Oral solution: 250 mg per 5 mL (50 mg per mL), clear colorless to slightly yellow solution

Gabapentin (Generic Neurontin ) was developed in 1993 and has indications for shingles (‘postherpetic neuralgia’) and partial-onset seizures. It has had a growing popularity in off-label uses for fibromyalgia, pain from a variety of causes, migraine, cocaine withdrawal, anxiety, and insomnia. A related compound, gabapentin encarbil (Horizant), is approved for shingles and restless leg syndrome. Pregabalin was developed in 2004 and is approved for nerve pain from diabetes and spinal cord injuries, fibromyalgia, and adjunctive treatment of partial-onset seizures. Although prescribed off-label for anxiety in the U.S., it is approved for this purpose in the U.K., where it is sometimes called the ‘new Valium’.

Gabapentin prevents seizures in a wide variety of models in animals, including generalized tonic-clonic and partial seizures. Gabapentin has no activity at GABAA or GABAB receptors of GABA uptake carriers of brain. Gabapentin interacts with a high-affinity binding site in brain membranes, which has recently been identified as an auxiliary subunit of voltage-sensitive Ca2+ channels.

gabapentinaction

However, the functional correlate of gabapentin binding is unclear and remains under study. Gabapentin crosses several lipid membrane barriers via system L amino acid transporters. In vitro, gabapentin modulates the action of the GABA synthetic enzyme, glutamic acid decarboxylase (GAD) and the glutamate synthesizing enzyme, branched-chain amino acid transaminase.

Results with human and rat brain NMR spectroscopy indicate that gabapentin increases GABA synthesis. Gabapentin increases non-synaptic GABA responses from neuronal tissues in vitro. In vitro, gabapentin reduces the release of several mono-amine neurotransmitters.

Gabapentin is used primarily to treat seizures and neuropathic pain. It is also commonly prescribed for many off-label uses, such as treatment of anxiety disorders, insomnia, and bipolar disorder. There are, however, concerns regarding the quality of the trials conducted and evidence for some such uses, especially in the case of its use as a mood stabilizer in bipolar disorder.

Gabapentin prevents pain responses in several animal models of hyperalgesia and prevents neuronal death in vitro and in vivo with models of the neurodegenerative disease amyotrophic lateral sclerosis (ALS). Gabapentin is also active in models that detect anxiolytic activity.

Although gabapentin may have several different pharmacological actions, it appears that modulation of GABA synthesis and glutamate synthesis may be important.