Gabapentin

Designed as a centrally acting GAGA agonist, with a lipophilic cyclohexane ring attached to the number 3 carbon atom of gamma amino butyric acid, Neurontin has no effect on GABA receptors.

Gabapentin or Neurontin as it is more commonly know was developed as an analogue of the neurotransmitter, gamma amino butyric acid, GABA by attaching a lipophilic cyclohexane ring to the number 3 carbon. The drug’s mechanism of action is unknown.  Despite the structural similarity to gamma amino butyric acid, it has no activity at normal GABA receptors. It has been shown to bind to a protein in cortical membranes with amino acid sequences identical to the α2δ subunit of type L voltage-sensitive calcium channels, yet it has no effect on the function of type T, N or L calcium channels in dorsal root ganglion cells.

Neurontin is moderately effective in the treatment of focal seizures and partial complex seizures although it is not yet approved for generalized epilepsy. It has been show act synergistically with many opiates, but data on its independent use as a painkiller is less clear due to problems with the study design. What is clear is that gabapentin’s greatest effect as a painkiller comes in dosage ranges, which overlap with its major side effects of somnolence and ataxia. Other side effects include weight gain and rarely peripheral edema.

The drug is excreted unchanged by the kidneys with a plasma half-life of 4 to 6 hours. Gabapentin neither induces nor blocks the hepatic metabolism of other drugs. Hepatotoxicity has been reported, but is rare.

The current primary use of Neurontin is in the treatment of chronic pain, especially neuropathic pain. It is very effective both in treating baseline chronic pain and in acute flair ups, but its usefulness is limited to the occurrence of side effect in the normal dosing range as mentioned above.

1 Comment

Leave Your Comment