What is gabapentin?

Gabapentin is an anti-epileptic medication, also called an anticonvulsant. It affects chemicals and nerves in the body that are involved in the cause of seizures and some types of pain.

Gabapentin is used in adults to treat nerve pain caused by herpes virus or shingles (herpes zoster).

The Horizant brand of gabapentin is also used to treat restless legs syndrome (RLS).

The Neurontin brand of gabapentin is also used to treatseizures in adults and children who are at least 3 years old.

NEURONTIN is a prescription medicine used to treat:

  • Pain from damaged nerves (postherpetic pain) that follows healing ofshingles (a painful rash that comes after a herpes zoster infection) in adults.
  • Partial seizures when taken together with other medicines in adults and children 3 years of age and older with seizures.

What are the FDA and non-FDA approved uses for gabapentin?

  • Gabapentin is approved for treating seizure disorders and nerve damage from herpes zoster (shingles, postherpetic neuralgia).
  • There are many non FDA-approved uses for gabapentin. These include
    • Alcohol withdrawal
    • Cocaine withdrawal
    • Hiccups
    • Restless leg syndrome
    • Hyperhidrosis
    • Headaches
    • Diabetic neuropathy
    • Hot flashes
    • Fibromyalgia

 

What are the side effects of gabapentin?

The most common side effects of gabapentin are:

  • Dizziness
  • Sleepiness
  • Ataxia
  • Fatigue
  • Drowsiness
  • Fluid retention (edema)
  • Hostility
  • Nausea
  • Vomiting
  • Difficulty speaking
  • Jerky movements
  • Unusual eye movements
  • Double vision
  • Tremors
  • Memory loss
  • Unsteadiness

Other adverse effects and serious side effects associated with gabapentin include:

  • Weight gain
  • Joint pain
  • Motion sickness
  • Blurred vision
  • Viral infection

Antiepileptic medications have been associated with an increased risk of suicidal thinking and behavior. Anyone considering the use of antiepileptic drugs must balance this risk of suicide with the clinical need. Patients who are started on therapy should be closely observed for clinical worsening, suicidal thoughts, or unusual changes in behavior.

Gabapentin Mechanism of Action

Neurontin (gabapentin) readily enters the brain and prevents seizures in a number of animal models of epilepsy. Gabapentin is structurally related to the neurotransmitter GABA (gamma-aminobutyric acid), but does not possess affinity for either GABAA or GABAB receptor.

Gabapentin binds with high affinity to the α2-δ (alpha-2-delta) subunit of voltage-gated calcium channels. Broad panel screening suggests it does not bind to other neurotransmitter receptors of the brain and does not interact with sodium channels.

The relevance of the binding activity of gabapentin to the anticonvulsant effects in animal models and in humans remains to be established (See DETAILED PHARMACOLOGY).

Gabapentin Overviews
Gabapentin Overviews

Gabapentin DOSAGE FORMS, COMPOSITION AND PACKAGING

Neurontin (gabapentin) capsules and tablets are supplied as follows:

100-mg capsules:

Hard gelatin CONI-SNAP® capsules with white opaque body and cap printed with “PD” on one side and “Neurontin /100 mg” on the other. -bottles of 100 capsules

300-mg capsules:

Hard gelatin CONI-SNAP® capsules with yellow opaque body and cap printed with “PD” on one side and “Neurontin /300 mg” on the other. -bottles of 100 capsules

400-mg capsules:

Hard gelatin CONI-SNAP® capsules with orange opaque body and cap printed with “PD” on one side and “Neurontin /400 mg” on the other. -bottles of 100 capsules

600 mg tablets:

White, elliptical, biconvex, film-coated tablet with bisecting score on both sides and debossed with “NT” and “16” on one side. -bottles of 100 tablets

800 mg tablets:

White, elliptical biconvex, film-coated tablet with bisecting score on both sides and debossed “NT” and “26” on one side. -bottles of 100 tablets

Capsules contain : gabapentin, lactose, corn starch, and talc, Capsule shells may contain : gelatin, titanium dioxide, silicon dioxide, sodium lauryl sulfate, yellow iron oxide, red iron oxide, and FD&C Blue No. 2.

Tablets contain : gabapentin, poloxamer 407 NF, copolyvidone, corn starch, magnesium stearate, hydroxypropylcellulose, talc and candelilla wax.