Neurontin

Generic name:

Gabapentin

Drug class:

Anticonvulsant; GABA analog

Dosage form:

• Capsule: 100 mg, 300 mg, 400 mg
• Tablet, immediate-release: 600 mg, 800 mg
• Oral solution: 250 mg per 5 mL

Root of administration:

Oral

Dose:

• Epilepsy (adjunctive): Initial 300 mg three times daily, titrate by 300 mg/day every 2–3 days to 900–1800 mg/day in three divided doses; max 3600 mg/day
• Postherpetic neuralgia: Day 1: 300 mg once, Day 2: 300 mg twice, Day 3: 300 mg three times; titrate to 1800 mg/day in three divided doses; max 3600 mg/day
• Renal impairment: Dosage adjustment required based on creatinine clearance
• Elderly: May require lower starting dose and slower titration

Mechanism of action:

Gabapentin binds to the α2δ subunit of voltage-gated calcium channels in the central nervous system, reducing excitatory neurotransmitter release and modulating neuronal excitability.

Drug usage cases:

• Adjunctive therapy for partial seizures with or without secondary generalization
• Treatment of postherpetic neuralgia
• Off-label: diabetic peripheral neuropathy
• Off-label: fibromyalgia
• Off-label: restless legs syndrome
• Off-label: migraine prophylaxis
• Off-label: bipolar disorder adjunct
• Off-label: hot flashes and menopausal symptoms
• Off-label: anxiety disorders
• Off-label: alcohol withdrawal and dependence

Drug contra indications:

• Hypersensitivity to gabapentin or any component of the formulation

Side effects:

• Dizziness
• Somnolence
• Fatigue
• Ataxia
• Peripheral edema
• Nystagmus
• Tremor
• Weight gain
• Nausea and vomiting
• Dry mouth
• Diplopia
• Blurred vision
• Memory impairment
• Infection
• Mood swings
• Depression
• Suicidal ideation
• Respiratory depression (with concomitant CNS depressants)
• Hypersensitivity reactions (angioedema, anaphylaxis, multi-organ sensitivity)

Warnings:

• CNS depression: risk of drowsiness, dizziness, ataxia
• Suicidal behavior and ideation: monitor mood changes
• Renal impairment: adjust dose based on creatinine clearance
• Discontinuation: taper gradually over at least one week to reduce risk of withdrawal seizures
• Respiratory depression: increased risk with opioids or other CNS depressants
• Hypersensitivity: multi-organ reactions reported; discontinue if suspected
• Use caution in elderly due to increased sensitivity to adverse effects

Use during pregnancy or breastfeeding:

Animal studies have shown fetal harm at clinically relevant exposures; human data are limited. Use only if potential benefit justifies potential risk. Gabapentin is excreted in human milk; monitor breastfed infants for sedation, poor feeding, and respiratory depression or consider alternative therapies.