Neurontin (Gabapentin) Capsules for Seizures and Pain
Neurontin is an oral gabapentinoid containing gabapentin. It is used in adults and children for partial-onset seizures and in adults for post-herpetic neuralgia. It is also widely used off-label for various neuropathic pain conditions.
- Active ingredients
- Gabapentin
- Manufacturer
- Pfizer
- Dosage forms
- capsule, tablet, oral solution
- Available dosages
- 100mg, 300mg, 400mg, 600mg, 800mg
- Category
- Neurological Medications
What is it?
Neurontin is the original brand of gabapentin, marketed by Pfizer (originally Parke-Davis) since its approval as an antiepileptic in 1993 and for post-herpetic neuralgia in 2002. It is supplied as oral capsules at 100mg, 300mg and 400mg, oral tablets at 600mg and 800mg, and oral solution. Neurontin is dispensed only on prescription and is classified as a controlled substance in some jurisdictions because of misuse concerns.
Active ingredients
Each capsule contains gabapentin as the sole active ingredient at 100mg, 300mg or 400mg. Gabapentin is a structural analogue of gamma-aminobutyric acid (GABA) but does not bind GABA receptors. It binds the alpha-2-delta auxiliary subunit of voltage-gated calcium channels in the central nervous system.
Forms and dosages
Neurontin is administered orally three times daily, with or without food. According to the prescribing information, the usual adult starting dose is 300mg on day 1, 300mg twice daily on day 2, 300mg three times daily on day 3, with subsequent titration based on response and tolerability up to 1800-3600mg per day in divided doses. Substantial dose reduction is required in renal impairment.
Indications
Neurontin is approved in adults and children aged 3 years and older as adjunctive therapy for partial-onset seizures, and in adults for post-herpetic neuralgia. According to international guidelines, gabapentin is also widely used off-label for diabetic peripheral neuropathy and other neuropathic pain syndromes, with the prescriber making the final decision based on individual response and clinical context.
How it works
Gabapentin binds the alpha-2-delta auxiliary subunit of voltage-gated calcium channels in the central nervous system, reducing presynaptic calcium influx and the release of excitatory neurotransmitters such as glutamate, noradrenaline and substance P. The result is anticonvulsant and analgesic effects, particularly in neuropathic pain pathways. Gabapentin does not bind GABA receptors despite its structural similarity to GABA.
Frequently asked questions
How is Neurontin different from Lyrica? ▾
Neurontin contains gabapentin and Lyrica contains pregabalin. Both bind the alpha-2-delta calcium channel subunit and are used in similar indications, but pregabalin has linear pharmacokinetics and higher bioavailability than gabapentin, which has saturable absorption at higher doses. Lyrica reaches effective plasma levels more reliably and at lower doses, although clinical efficacy in neuropathic pain at adequate doses is broadly comparable. The choice is made by the prescriber.
Why must Neurontin be titrated? ▾
Neurontin requires gradual titration to minimise side effects, particularly drowsiness, dizziness and ataxia, which are most prominent during initiation. According to the prescribing information, typical titration starts at 300mg on day 1, 300mg twice daily on day 2, 300mg three times daily on day 3, and increased further as needed. Therapeutic doses are usually 1800-3600mg per day in divided doses. Sudden discontinuation should be avoided.
Why must the dose be reduced in kidney disease? ▾
Gabapentin is excreted unchanged in urine, so renal impairment substantially increases plasma concentrations and the risk of adverse effects, including sedation, ataxia and cognitive impairment. According to the prescribing information, the dose is reduced based on creatinine clearance, including in patients on dialysis where supplemental doses are given after sessions. Renal function should be assessed before treatment and periodically thereafter.
Is Neurontin a controlled substance? ▾
Gabapentin has been associated with misuse and physical dependence, particularly in patients with substance use disorders or in combination with opioids. It is classified as a controlled substance in some jurisdictions including some U.S. states, but not at the federal level. According to regulatory communications, prescribers should screen for substance use history and monitor for misuse, particularly at higher doses or in combination with opioids.
What are the main contraindications for Neurontin? ▾
Neurontin is contraindicated in known hypersensitivity to gabapentin or its excipients. Caution is required in renal impairment (with mandatory dose adjustment), in concurrent CNS depressants including opioids, in older adults, and during pregnancy and breastfeeding. According to the prescribing information, the medical history must be reviewed by a clinician before any prescription, particularly in patients with chronic kidney disease or substance use history.
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