Characteristic of neuropathic pain
Neuropathic pain refers to the pain that occurs with an organic lesion or a disorder in the function of various parts of the nervous system. The cause of the neuropathic pain can be the nervous system damage at any level, from the peripheral nerves to the cortex of the large hemispheres. In neurology, the term “neuropathic” usually indicates a peripheral nerve damage. In this regard, there may be a misconception that neuropathic pain is a pain that occurs solely with peripheral neuropathy or polyneuropathy. Here again, it should be emphasized that the term “neuropathic pain” indicates a pain syndrome that occurs when the peripheral or central nervous system is damaged or disordered at any level.
The mechanism of action of Neurontin
Neurontin was originally synthesized as a structural analog of gamma-aminobutyric acid (GABA) and belongs to widely used antiepileptic drugs. Based on the results obtained in experimental animal models, it is shown that Neurontin enhances the synthesis of GABA, has a modulating effect on NMDA receptors, blocks the a2d subunit of calcium channels, reduces the release of monoamines, reduces the synthesis and transport of glutamate, and reduces the frequency of action potentials of peripheral nerves. Probably the combination of the above mechanisms of action provides high therapeutic efficacy of Neurontin in various forms of neuropathic pain syndrome.
Properties of Neurontin
The main active substance of Neurontin is Gabapentin, which has a proven ability to prevent the onset of partial seizures. The drug is prescription one and clear indications are required for its administration.
The drug is well tolerated, side effects occur very rarely. The most frequent ones can be mild dizziness or drowsiness. The drug has no serious interactions with other drugs. However, one should refrain from combining Neurontin with alcohol, tranquilizers, antihistamines, barbiturates, anticonvulsants, sleeping pills, muscle relaxants, and narcotics. The combination of Neurontin with other analgesic drugs (lidocaine, antidepressants) enhances the therapeutic effect.
The concentration of Neurontin in the plasma reaches a peak 2-3 hours after the intake. The interval between doses of the drug should not exceed 12 hours. Bioavailability is 60%. Eating does not affect the pharmacokinetics of Neurontin. Due to the fact that antacid drugs (Maalox) reduce the concentration of Neurontin in the blood, it is recommended to take it no earlier than 2 hours after taking antacids. The drug is excreted mainly by the kidneys, not metabolized in the liver. In renal pathology, in order to avoid an increase in the concentration of Neurontin in the blood, a dose adjustment is made in accordance with the creatinine clearance.
When treating neuropathic pain with Neurontin, side effects are observed more often in children than in adults., Neurontin is slowly excreted from the body in the elderly, and therefore the dose of the drug should be reduced. It is known that Neurontin is excreted in breast milk, but the effect of the drug on the child has not been studied. Also, the possible teratogenic effect of the drug is unknown.
The appointment of Neurontin for any forms of treatment of the neuropathic pain is carried out according to the schedule prescribed by the doctor. Most often, the daily therapeutic dose of Neurontin is 1800-3600 mg/day.
Neurontin in the treatment of a peripheral polyneuropathy.
According to the results of the research, Neurontin is currently one of the most effective drugs in the treatment of diabetes in diabetic polyneuropathy. The recommended dose of Neurontin for the treatment of neuropathic pain in diabetic polyneuropathy is 1800-2400 mg/day. Treatment begins with the dose of 300 mg/day, then within the first week, it should be increased to 1800 or 2400 mg/day. The course of treatment should be conducted continuously for 2-4 months.
Neurontin in the treatment of a pain in postherpetic neuralgia.
The efficacy of Neurontin in postherpetic neuralgia in a large randomized study was shown in 229 patients . At the same time, there was not only a marked decrease in the pain syndrome, but also an improvement in sleep, mood and quality of life of patients. The dose of Neurontin for the treatment of postherpetic neuralgia is 1800-3600 mg/day for 2-4 months at an initial dose of 300 mg.
Neurontin in the treatment of multiple sclerosis.
A marked clinical improvement in pain syndrome and spasticity was proved during numerous prospective, double-blind, placebo-controlled studies of Neurontin effectiveness in 21 patients with multiple sclerosis. Significant improvement or complete disappearance of the pain syndrome was obtained with the use of Neurontin in many studies. A significant reduction in spasticity and muscle cramp, significant improvement or complete disappearance of the pain syndrome during the treatment with Neurontin in patients with multiple sclerosis was observed.
The initial dose of the drug is 300 mg/day, and then it should be increased to 900 mg and higher during 3 weeks. The average dose reaches 900 mg (range from 600 to 2400 mg/day).