Adult: Initially, 300 mg once daily on the 1st day, 300 mg bid on the 2nd day, and 300 mg tid on the 3rd day. Alternatively, 300 mg tid on the 1st day. Thereafter, doses may be further increased in 300 mg daily increments every 2-3 days according to individual response and tolerability. Effective dosing range: 900-3,600 mg daily. Total daily dose must be given in 3 equally divided doses, at max dose interval not exceeding 12 hours. Child: ≥6 years Initially, 10-15 mg/kg daily, may be titrated over a period of approx 3 days until effective dose is achieved. Effective dosing range: 25-35 mg/kg daily. Max: 50 mg/kg daily. Total daily dose must be given in 3 equally divided doses at max dose interval not exceeding 12 hours.
Oral Neuropathic pain
Adult: Initially, 300 mg once daily on the 1st day, 300 mg bid on the 2nd day, and 300 mg tid on the 3rd day. Alternatively, 900 mg daily in 3 equally divided doses as starting dose. Thereafter, doses may be further increased in 300 mg daily increments every 2-3 days according to individual response and tolerability. Max: 3,600 mg daily.
Oral Postherpetic neuralgia
Adult: As gabapentin enacarbil: Modified-release preparation: Initially, 600 mg once daily in the morning for 3 days, then increased to 600 mg bid.
Oral Restless leg syndrome
Adult: As gabapentin enacarbil: Modified-release preparation: Moderate to severe: 600 mg once daily at approx 5 pm.
Epilepsy, Neuropathic pain: All doses are given in 3 divided doses. In anuric patient undergoing haemodialysis who never received gabapentin: Loading dose: 300-400 mg, followed by 200-300 mg after each 4-hour haemodialysis. In renally impaired patient undergoing haemodialysis: additional 200-300 mg in the maintenance dose after each 4-hour haemodialysis.
300 mg on alternate days to 300 mg daily.
300 mg on alternate days to 600 mg daily.
300-900 mg daily.
600-1,800 mg daily.
Restless leg syndrome: As gabapentin enacarbil: Modified-release preparation: Haemodialysis: Not recommended.
300 mg on alternate days.
300 mg daily.
Initially, 300 mg daily, increased to 600 mg daily, if necessary.
Postherpetic neuralgia: As gabapentin enacarbil: Modified-release preparation: Haemodialysis: Maintenance: 300 mg after each dialysis, may increase to 600 mg if necessary. All doses are based on individual response and tolerability.
Maintenance: 300 mg in the morning on alternate days, may increase to 300 mg once daily in the morning if needed.
Titration: 300 mg in the morning on day 1 and 3; Maintenance: 300 mg daily in the morning, may increase to 300 mg bid if needed; Tapering: If taking 300 mg bid, may reduce dose to 300 mg once daily in the morning for 1 week; If taking 300 mg once daily, no tapering needed.
Titration: 300 mg in the morning for 3 days; Maintenance: 300 mg bid, may increase to 600 mg bid as needed; Tapering: May reduce current dose to once daily in the morning for 1 week.
May be taken with or without food.
Patients with mixed seizures including absences, compromised respiratory function, respiratory or neurological disease, history of substance abuse (e.g. alcohol, benzodiazepines, cannabis, cocaine, opioids). Concomitant use with opioids. Avoid abrupt withdrawal. Renal impairment. Children and elderly. Pregnancy and lactation.
Significant: Suicidal ideation and behaviour, neuropsychiatric effects in children (e.g. emotional lability, hostility, changes in behaviour and thinking, hyperkinesia), acute pancreatitis, respiratory depression, anaphylaxis, angioedema. Blood and lymphatic system disorders: Leucopenia, thrombocytopenia. Ear and labyrinth disorders: Vertigo, tinnitus. Eye disorders: Nystagmus, amblyopia, diplopia. Gastrointestinal disorders: Nausea, vomiting, diarrhoea, dry mouth, dental abnormality, dyspepsia, gingivitis, flatulence, constipation. General disorders and admin site conditions: Fatigue, fever, peripheral oedema, abnormal gait, asthenia, malaise. Infections and infestations: Viral infection, pneumonia, otitis media. Injury, poisoning and procedural complications: Accidental injury, fracture. Investigations: Weight gain, decreased WBC. Metabolism and nutrition disorders: Anorexia, increased appetite. Musculoskeletal and connective tissue disorders: Back pain, arthralgia, myalgia. Nervous system disorders: Somnolence, dizziness, headache, ataxia, amnesia, tremor. Psychiatric disorders: Confusion, depression, nervousness, anxiety. Reproductive system and breast disorders: Impotence. Respiratory, thoracic and mediastinal disorders: Dyspnoea, bronchitis, cough, rhinitis. Skin and subcutaneous tissue disorders: Rash, pruritus, acne. Vascular disorders: Hypertension, vasodilatation. Potentially Fatal: Multiorgan hypersensitivity such as drug reaction with eosinophilia and systemic symptoms (DRESS).
This drug may cause dizziness and drowsiness, if affected, do not drive or operate machinery.
Monitor renal function at baseline and periodically thereafter. Assess for signs of multiorgan hypersensitivity and suicidality (e.g. suicidal thoughts, depression, behavioural changes).
Symptoms: Dizziness, drowsiness, double vision, slurred speech, mild diarrhoea, lethargy, and loss of consciousness. Management: Symptomatic and supportive treatment. May consider haemodialysis in patients with severe renal impairment.
Increased risk of CNS depression (e.g. somnolence, sedation and respiratory depression) with opioids (e.g. morphine). May reduce bioavailability with antacids. May reduce renal clearance with cimetidine.
May enhance CNS depressant effect of alcohol.
May lead to false-positive result with certain dipstick test for total urine protein.
Description: Gabapentin is structurally related to neurotransmitter GABA. It does not bind to GABAA or GABAB receptors nor influence the synthesis or uptake of GABA. It binds with high affinity to the α-2-δ-1 subunit of voltage-gated Ca channels, thereby modulating the release of excitatory neurotransmitters which participate in epileptogenesis and nociception. Pharmacokinetics: Absorption: Variably absorbed from the gastrointestinal tract. Bioavailability: Approx 60% (gabapentin). As gabapentin enacarbil: Approx 75% (with food); 42-65% (fasting). Time to peak plasma concentration: Approx 2-4 hours (gabapentin); As gabapentin enacarbil: 5 hours (fasting); 7.3 hours (with food). Distribution: Widely distributed in the body. Crosses placenta and enters breast milk. Volume of distribution: 58±6 L (gabapentin); 76 L (gabapentin enacarbil). Plasma protein binding: <3%. Metabolism: As gabapentin enacarbil: Undergoes extensive first-pass metabolism mainly in enterocytes and to a lesser extent in the liver to form gabapentin, CO2, acetaldehyde and isobutyric acid. Excretion: As gabapentin: Mainly via urine (as unchanged drug). As gabapentin enacarbil: Mainly via urine (94%); faeces (5%). Elimination half-life: Approx 5-7 hours.
Conventional tab and cap: Store below 25°C. Oral solution: Store between 2-8°C. Extended-release tab: Store at 25°C. Protect from moisture.