Gabapentin

Alpha-2-delta ligand·Neurology - Anticonvulsants

Neuropathic pain (diabetic neuropathy, post-herpetic neuralgia), focal seizures

Authority requiredPBSGABAPENTINOIDNeurontin, Pendine400 mg tablet+2

Max Dose

3600 mg/day

Half-life

5-7 h

Bioavailability

INVERSE DOSE

Sedation

COMMON

Rapid Summary

Overview

Gabapentinoid. Designed for epilepsy but used almost exclusively today for neuropathic pain. Highly unique pharmacokinetics: the more you swallow, the less you absorb.

Maximum Dose

Max 3600 mg/day (e.g., 1200 mg TDS).

Clinical Focus

Synergistic respiratory depression when mixed with Opioids. Heavily renally cleared.

Bottom Line

Gabapentin is an anticonvulsant widely used for neuropathic pain, but has limited evidence for many off-label uses and increasing Schedule 8 restrictions due to misuse and dependence potential.

Formulation & Access

Brand Names

Neurontin, Pendine

Oral Routes

Capsules (100, 300, 400 mg). Tablets (600, 800 mg).

Prescribing & PBS

Authority Required (PBS) for neuropathic pain/epilepsy.

Indications & Use

Primary

PBSTGA

Neuropathic pain (diabetic neuropathy, post-herpetic neuralgia), focal seizures.

Off-Label

OFF

Restless legs syndrome, severe anxiety, alcohol withdrawal adjunct.

Clinical Place

First-line baseline agent for nerve pain. Less abuse potential than Pregabalin.

Quick reference

Class & Role

Alpha-2-delta ligand — Gabapentinoid.

Route / Formulation

Capsules (100, 300, 400 mg). Tablets (600, 800 mg). (Neurontin, Pendine)

Usual Dose & Max

Day 1: PO 300 mg OD. Day 2: 300 mg BD. Day 3: 300 mg TDS. Titrate up weekly. Target 1800 - 3600 mg/day in divided doses. Max 3600 mg/day (e.g., 1200 mg TDS).

Key Indication Doses

Neuropathic Pain: Day 1: PO 300 mg OD. Day 2: 300 mg BD. Day 3: 300 mg TDS. Titrate up weekly. Target 1800 - 3600 mg/day in divided doses. Renal Impairment: If eGFR 30-59, Max 1400 mg/day. If eGFR 15-29, Max 700 mg/day. If eGFR < 15, Max 300 mg/day.

Best Uses

Gabapentin is an anticonvulsant widely used for neuropathic pain, but has limited evidence for many off-label uses and increasing Schedule 8 restrictions due to misuse and dependence potential.

Avoid / Cautions

None strictly absolute, but severe caution in respiratory failure or end-stage renal disease without dose adjustment. Pregnancy Category B1.

Key Risks

Neurological: Somnolence, dizziness, ataxia, fatigue (Extremely common, requires glacial titration). Respiratory: Severe respiratory depression (Only a major risk if combined with opioids/benzos or in unadjusted renal failure). Metabolic: Weight gain, peripheral edema.

Key Interactions

Opioids. The combination of Gabapentin + Oxycodone/Morphine is a leading cause of accidental respiratory overdose in chronic pain patients. Antacids (Magnesium/Aluminium) physically block absorption in the gut. Separate by 2 hours.

Monitoring

Baseline and routine eGFR to calculate safe maximum dose. Assess for falls risk in the elderly, as ataxia and dizziness are severe during week 1.

Clinical Pearl

Gabapentin requires a specific amino acid transporter to cross the gut wall. This transporter gets saturated quickly. If you swallow 300mg, 60% absorbs. If you swallow 1200mg at once, only 20% absorbs. You MUST divide the dose TDS to get the drug into the blood.

Access

Authority requiredNeurontin, Pendine400 mg tablet

Brand: Neurontin, Pendine
PBS status: Authority required
Formulation: Capsules (100, 300, 400 mg)

Gabapentin

Alpha-2-delta ligand·Neurology - Anticonvulsants

Neuropathic pain (diabetic neuropathy, post-herpetic neuralgia), focal seizures

Authority requiredPBSGABAPENTINOIDNeurontin, Pendine400 mg tablet+2

Max Dose

3600 mg/day

Half-life

5-7 h

Bioavailability

INVERSE DOSE

Sedation

COMMON

Rapid Summary

Overview

Gabapentinoid. Designed for epilepsy but used almost exclusively today for neuropathic pain. Highly unique pharmacokinetics: the more you swallow, the less you absorb.

Maximum Dose

Max 3600 mg/day (e.g., 1200 mg TDS).

Clinical Focus

Synergistic respiratory depression when mixed with Opioids. Heavily renally cleared.

Bottom Line

Gabapentin is an anticonvulsant widely used for neuropathic pain, but has limited evidence for many off-label uses and increasing Schedule 8 restrictions due to misuse and dependence potential.

Formulation & Access

Brand Names

Neurontin, Pendine

Oral Routes

Capsules (100, 300, 400 mg). Tablets (600, 800 mg).

Prescribing & PBS

Authority Required (PBS) for neuropathic pain/epilepsy.

Indications & Use

Primary

PBSTGA

Neuropathic pain (diabetic neuropathy, post-herpetic neuralgia), focal seizures.

Off-Label

OFF

Restless legs syndrome, severe anxiety, alcohol withdrawal adjunct.

Clinical Place

First-line baseline agent for nerve pain. Less abuse potential than Pregabalin.

Quick reference

Class & Role

Alpha-2-delta ligand — Gabapentinoid.

Route / Formulation

Capsules (100, 300, 400 mg). Tablets (600, 800 mg). (Neurontin, Pendine)

Usual Dose & Max

Day 1: PO 300 mg OD. Day 2: 300 mg BD. Day 3: 300 mg TDS. Titrate up weekly. Target 1800 - 3600 mg/day in divided doses. Max 3600 mg/day (e.g., 1200 mg TDS).

Key Indication Doses

Best Uses

Gabapentin is an anticonvulsant widely used for neuropathic pain, but has limited evidence for many off-label uses and increasing Schedule 8 restrictions due to misuse and dependence potential.

Avoid / Cautions

None strictly absolute, but severe caution in respiratory failure or end-stage renal disease without dose adjustment. Pregnancy Category B1.

Key Risks

Key Interactions

Monitoring

Baseline and routine eGFR to calculate safe maximum dose. Assess for falls risk in the elderly, as ataxia and dizziness are severe during week 1.

Clinical Pearl

Access

Authority requiredNeurontin, Pendine400 mg tablet

Brand: Neurontin, Pendine
PBS status: Authority required
Formulation: Capsules (100, 300, 400 mg)