Gabapentin is an anticonvulsant medication used in the management of peripheral neuropathic pains, postherpetic neuralgia, and partial-onset seizures.
It was originally developed as a novel anti-epileptic for the treatment of certain types of seizures - today it is also widely used to treat neuropathic pain.
Gabapentin has some stark advantages as compared with other anti-epileptics, such as a relatively benign adverse effect profile, wide therapeutic index, and lack of appreciable metabolism making it unlikely to participate in pharmacokinetic drug interactions.
In the United States, gabapentin is officially indicated for the treatment of postherpetic neuralgia in adults and for the adjunctive treatment of partial-onset seizures, with or without secondary generalization. In Europe, gabapentin is indicated for adjunctive therapy in the treatment of partial-onset seizures, with or without secondary generalization. It is also used in adults for the treatment of various types of peripheral neuropathic pain, such as painful diabetic neuropathy.
Gabapentin may also be used for purposes not listed in this medication guide.
Gabapentin is an anti-convulsant medication that inhibits the release of excitatory neurotransmitters, allowing for its use against pathologic neurotransmission such as that seen in neuropathic pain and seizure disorders.
Gabapentin is ineffective in absence seizures and should be used in caution in patients with mixed seizure disorders involving absence seizures.
Gabapentin has been associated with drug reaction with eosinophilia and systemic symptoms (DRESS), otherwise known as multi-organ hypersensitivity. This reaction can prove fatal and early symptoms such as fever, lymphadenopathy, and rash should be promptly investigated.
The precise mechanism through which gabapentin exerts its therapeutic effects is unclear.
There is evidence that chronic pain states can cause an increase in the expression of α2δ subunits and that these changes correlate with hyperalgesia. Gabapentin appears to inhibit the action of α2δ-1 subunits, thus decreasing the density of pre-synaptic voltage-gated calcium channels and subsequent release of excitatory neurotransmitters. It is likely that this inhibition is also responsible for the anti-epileptic action of gabapentin.
Metabolism: Gabapentin is not appreciably metabolized in humans, metabolites account for less than 1% of an administered dose, with the remainder being excreted as unchanged parent drug in the urine.
Absorption: Absorption of gabapentin is thought to occur solely via the intestines. As this process is saturable, the oral bioavailability of gabapentin is inversely proportional to the administered dose - the oral bioavailability of a 900mg/day regimen is approximately 60%, whereas a 4800mg/day regimen results in only 27% bioavailability. Food has no appreciable effect on gabapentin absorption.
Route of elimination: Gabapentin is eliminated solely in the urine as unchanged drug.
Half life: The elimination of gabapentin in patients with normal renal function is 5-7 hours.
All medicines may cause side effects, but many people have no, or minor, side effects. Some medical conditions may interact with Gabapentin.
Tell your doctor or pharmacist if you have any medical conditions.
Common alprazolam side effects may include: CNS depression (e.g. dizziness, drowsiness, slurred speech, lethargy, loss of consciousness) and gastrointestinal symptoms such as diarrhea.
This is not a complete list of all side effects that may occur. If you have questions about side effects, contact your health care provider.
