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Gabapentinoid (Alpha-2-Delta Calcium Channel Ligand) Pregnancy: Avoid if possible — increased risk of congenital malformations; if essential for epilepsy, continue with folate supplementation

Gabapentin

Brand names: Neurontin

Adult dose

Dose: Neuropathic pain: starting 300 mg OD (day 1), 300 mg BD (day 2), 300 mg TDS (day 3), titrate up to 3600 mg/day. Epilepsy: 900–3600 mg/day in 3 divided doses.
Route: Oral
Frequency: TDS
Max: 3600 mg/day
Class C controlled drug (UK, 2019). Misuse potential. Titrate slowly to minimise side effects. Lower doses in renal impairment.

Paediatric dose

Dose: 3.3 mg/kg
Route: Oral
Frequency: Three times daily (titration day 1; total 10 mg/kg/day)
Max: 1200 mg per dose (3600 mg/day) — paediatric target 25–35 mg/kg/day
Concentration: 250 mg/5 mL oral solution mg/ml
BNFc child 6–11 years (focal seizures): day 1 10 mg/kg ON, day 2 10 mg/kg BD, day 3+ 10 mg/kg TDS (target 25–35 mg/kg/day in 3 divided doses, max 70 mg/kg/day or 3600 mg/day, whichever lower). Child 12+: as adult — start 300 mg ON, titrate. Not licensed for neuropathic pain in children.

Dose adjustments

Renal

Significant reduction required: eGFR 30–60: max 1400 mg/day; eGFR 15–30: max 700 mg/day; eGFR <15: max 300 mg OD (or after haemodialysis)

Hepatic

No dose adjustment required (not hepatically metabolised)

Paediatric weight-based calculator

BNFc child 6–11 years (focal seizures): day 1 10 mg/kg ON, day 2 10 mg/kg BD, day 3+ 10 mg/kg TDS (target 25–35 mg/kg/day in 3 divided doses, max 70 mg/kg/day or 3600 mg/day, whichever lower). Child 12+: as adult — start 300 mg ON, titrate. Not licensed for neuropathic pain in children.

Clinical pearls

  • Class C controlled drug since April 2019 — must be on FP10 (handwritten) or EPS with controlled drug requirements
  • MHRA 2019 warning: gabapentinoids + opioids increase risk of respiratory depression and death
  • Abrupt discontinuation: risk of seizures and withdrawal — always taper slowly (reduce by 300 mg every 3–7 days)
  • Renal dose adjustment is critical — check BNF tables carefully

Contraindications

  • Acute pancreatitis (relative)

Side effects

  • Somnolence and dizziness (most common)
  • Ataxia
  • Fatigue
  • Peripheral oedema
  • Weight gain
  • Blurred vision
  • Dependence and withdrawal (abrupt discontinuation causes seizures)
  • Respiratory depression (especially in combination with opioids)

Interactions

  • Opioids — additive CNS depression and respiratory depression (MHRA safety warning 2019)
  • Antacids (aluminium/magnesium) — reduce gabapentin absorption by 20% (separate by 2h)
  • Morphine — increases gabapentin AUC by 44%
  • Alcohol — additive CNS depression

Monitoring

  • Renal function (dose adjustment)
  • Sedation and ataxia
  • Respiratory function (especially with opioids)
  • Signs of dependence or misuse

Reference: BNFc; BNF; MHRA Drug Safety Update 2019 (Gabapentinoids + opioids); NICE NG193 Neuropathic Pain. Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

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