Gabapentin oral
- Drugs List
- Therapeutic Indications
- Dosage
- Contraindications
- Precautions and Warnings
- Pregnancy and Lactation
- Side Effects
- Monograph
Presentation
Oral formulations containing gabapentin
Drugs List
Therapeutic Indications
Uses
Epilepsy-partial seizures with/without secondary generalisation-adjunctive
Epilepsy-partial seizures with/without secondary generalisation-monotherapy
Neuropathic pain
Unlicensed Uses
Menopausal symptoms in women with breast cancer
Migraine (prophylaxis)
Dosage
Adults
Epilepsy
The total daily dose should be divided into three single doses.
Titrate dose to effective level (usually 900mg to 3600mg per day).
Day 1: 300mg once daily.
Day 2: 300mg twice daily.
Day 3: 300mg three times daily.
Alternatively, administer 300mg three times on day 1.
Thereafter, dose can be increased using increments of 300mg per day, every two to three days, up to a maximum of 3600mg daily. Slower titration of dosage may be more appropriate for some patients.
The minimum time to reach a dose of 1800mg/day is one week.
The minimum time to reach a dose of 2400mg/day is two weeks.
The minimum time to reach a dose of 3600mg/day is three weeks.
The maximum time between doses should not exceed 12 hours to prevent breakthrough convulsions. In long-term clinical studies, doses up to 4800mg/day have been well tolerated.
If gabapentin is discontinued and/or alternate anti-convulsant medicine is added to therapy, this should be done gradually over a minimum period of one week.
Neuropathic Pain
Titrate dose to a maximum of 3600mg per day.
Day 1: 300mg once daily.
Day 2: 300mg twice daily.
Day 3: 300mg three times daily.
Alternatively, administer 300mg three times on day 1.
Thereafter, dose can be increased using increments of 300mg per day every two to three days. Slower titration of dosage may be more appropriate for some patients.
The minimum time to reach a dose of 1800mg/day is one week.
The minimum time to reach a dose of 2400mg/day is two weeks.
The minimum time to reach a dose of 3600mg/day is three weeks.
For the treatment of peripheral neuropathic pain, safety and efficacy have not been established for treatment periods exceeding five months. If patients require therapy exceeding five months, the clinical status of the patient and the need for additional therapy should be assessed.
Discontinuation of gabapentin should be gradual over a period of at least one week.
Migraine prophylaxis (unlicensed)
Initially, 300mg daily increased according to response.
Maximum dose: 2.4g daily in divided doses.
Menopausal symptoms in women with breast cancer (unlicensed)
Initial doses should be low and titrated over three days
Maintenance dose: 300mg three times a day
Elderly
(See Dosage; Adult) Dose reduction may be necessary because of declining renal and respiratory function with age.
Children
Epilepsy - monotherapy
Children aged 12 years and over
(See Dosage; Adults)
Epilepsy - adjunctive therapy
Children aged 12 years and over
(See Dosage; Adults)
Children aged 6 to 12 years of age
The starting dose should range from 10 to 15mg/kg/day. The effective dose is reached by upward titration over a period of about three days. The effective dose of gabapentin is 25 to 35mg/kg/day.
The total daily dose should be divided into three single doses. The maximum time between doses should not exceed 12 hours to prevent breakthrough convulsions. In a long-term clinical study, doses up to 50mg/kg/day have been well tolerated.
The following alternative dosage schedule may be suitable:
Day 1: 10mg/kg once daily (maximum of 300mg).
Day 2: 10mg/kg twice daily (maximum of 300mg).
Day 3: 10mg/kg three times daily (maximum of 300mg).
Usual dose: 25 to 35mg/kg daily in three divided doses. Maximum: 70mg/kg daily in three divided doses. Doses over 50mg/kg in are not licensed in children under 12.
Children aged 2 to 6 years (unlicensed)
Day 1: 10mg/kg once daily (maximum of 300mg).
Day 2: 10mg/kg twice daily (maximum of 300mg).
Day 3: 10mg/kg three times daily (maximum of 300mg).
Usual dose: 30 to 70mg/kg daily in three divided doses.
Some children may not tolerate daily increments; longer intervals (up to weekly) may be more appropriate.
Patients with Renal Impairment
Creatinine clearance 50 to 79ml/minute
600mg to 1800mg in three divided doses.
Creatinine clearance 30 to 49ml/minute
300mg to 900mg in three divided doses.
Creatinine clearance 15 to 29ml/minute
150mg to 600mg in three divided doses.
The 150mg daily dose should be given by administering 300mg in three divided doses every other day.
Creatinine clearance less than 15ml/minute
150mg to 300mg in three divided doses.
The 150mg daily dose should be given by administering 300mg in three divided doses every other day.
In these patients, the total daily dose should be reduced in proportion to creatinine clearance (e.g. patients with creatinine clearance of 7.5ml/minute should receive half of the dose given to patients with creatinine clearance of 15ml/minute).
Haemodialysis patients
For anuric patients undergoing haemodialysis who have never received gabapentin, a loading dose of 300mg to 400mg is recommended followed by 200mg to 300mg of gabapentin after each 4 hours of haemodialysis.
There should be no treatment with gabapentin on dialysis-free days.
For renally impaired patients undergoing haemodialysis, use the total daily dose as described above. In addition to this, 200mg to 300mg gabapentin should be administered after each 4 hours of haemodialysis.
Additional Dosage Information
In patients in poor general health (e.g. low body weight or post-organ transplant), dosage should be titrated more slowly by using smaller dose strengths or increasing the intervals between dose increases.
Contraindications
Children under 2 years
Precautions and Warnings
Children aged 2 to 6 years
Patients over 65 years
Suicidal ideation
Breastfeeding
Diabetes mellitus
Galactosaemia
Glucose-galactose malabsorption syndrome
Haemodialysis
History of alcohol abuse
History of drug misuse
History of psychosis
Lactose intolerance
Pregnancy
Renal impairment - creatinine clearance below 80ml/min
Respiratory impairment
Patients at risk of suicide should be closely supervised
Patients with diabetes may experience fluctuations in blood glucose
Reduce dose in patients with renal impairment
Sodium content of formulation may be significant
Advise ability to drive/operate machinery may be affected by side effects
Folic acid 5mg daily required pre-conception to end of 1st trimester
Contains potassium; caution in low potassium diets
Some formulations contain lactose
All changes to existing regimen should be over a minimum of one week
May cause an increase in seizure frequency or onset of new seizure types
May cause respiratory depression
Monitor children and adolescents on long-term therapy
Monitor for signs of tolerance and dependence
Monitor patients with a history of alcoholism and drug abuse
Potential for drug abuse
Advise patient to report any new or worsening depression/suicidal ideation
Advise patients/carers to seek medical advice if suicidal intent develops
Consider discontinuation if pancreatitis occurs
May cause dependence
May affect urine protein dipstick test
Do not withdraw this drug suddenly
Discontinue if severe hypersensitivity reactions occur
Not licensed for use in children under 6 years
Advise patient not to take St John's wort concurrently
Advise that effects are potentiated by CNS depressants (including alcohol)
Treatment with gabapentin carries a risk of central nervous system depression (including severe respiratory depression), even without concomitant opioids. Dose adjustments should be considered in high risk patient groups, including the elderly, patients with a compromised respiratory function, patients with respiratory or neurological disease, renally impaired patients and patients taking concomitant CNS depressants.
Antiepileptic treatment is associated with a small increased risk of suicidal thoughts and behaviour; available data suggest that the increased risk applies to all antiepileptics and is seen as early as one week after starting treatment.
The available evidence does not define whether the risk of suicidal thoughts and behaviour differs between antiepileptics. Patients should not stop or switch treatment on the basis of this information and without speaking to a healthcare professional.
Not considered effective for treatment of primary generalised seizures (e.g. absence seizures). Gabapentin may aggravate these seizures in some patients. Gabapentin should therefore be used with caution in patients with mixed seizures, including absence seizures.
Elderly patients may require dosage adjustment due to declining renal function with age. Elderly patients may be more likely to experience somnolence, peripheral oedema and asthenia.
Severe, life-threatening, systemic hypersensitivity reactions such as drug rash with eosinophilia and systemic symptoms (DRESS) have been reported. Early manifestations of hypersensitivity, such as fever or lymphadenopathy, may be present even though the rash is not evident. If signs or symptoms are present, evaluate the patient immediately and discontinue gabapentin if an alternative aetiology for the signs and symptoms cannot be established.
Do not withdraw this drug suddenly. Abrupt withdrawal in epileptic patients may cause status epilepticus. If gabapentin is to be discontinued or an alternative anticonvulsant medication is added to the therapy, this should be done gradually over a minimum of 1 week.
The effects of long term therapy (over 36 weeks) on learning, intelligence and development in children and adolescents have not been adequately studied. The benefits of prolonged therapy must be weighed against the risks in these patients.
Antacids containing aluminium and magnesium reduce the bioavailability of gabapentin by up to 24%. Gabapentin should be administered at least 2 hours after antacids.
Pregnancy and Lactation
Pregnancy
Gabapentin should be used with caution in pregnancy.
Gabapentin crosses the human placenta. The manufacturers advise not using gabapentin during pregnancy unless the potential benefit to the mother outweighs the potential risk to the foetus. Multiple antiepileptic drug therapy may be associated with a higher risk of congenital malformations than monotherapy, therefore it is recommended that monotherapy is used whenever possible.
Animal studies have shown reproductive toxicity although the potential risk to humans is unknown.
Specialist advice should be given to women who are likely to become pregnant or who are of childbearing potential and the need for treatment in particular for epileptic patients, should be reviewed when a woman is planning to become pregnant. No sudden discontinuation of therapy should be undertaken as this may lead to breakthrough seizures, which could have serious consequences for both mother and child. Developmental delay in children of mothers with epilepsy has been observed rarely.
Schaefer (2015) concludes that available human and animal data do no indicate a substantial teratogenic risk for gabapentin monotherapy, and termination of an exposed pregnancy is unnecessary.
Lactation
Use gabapentin with caution in breastfeeding.
Gabapentin is excreted in human milk but the effect on the nursing infant is unknown. Caution should be exercised when gabapentin is administered to a breastfeeding mother. Gabapentin should be used in breastfeeding mothers only if the benefits clearly outweigh the risks.
Close observation of the infant is recommended, and if symptoms occur that could be associated with maternal drug therapy, consider monitoring the infant's serum concentration. LactMed (2018) suggests to monitor infant for drowsiness, adequate weight gain and developmental milestones, especially in younger, exclusively breastfed infants.
Side Effects
Abdominal pain
Abnormal thinking
Accidental injury
Acne
Acute renal failure
Aggression
Allergic reaction
Alopecia
Altered liver function tests
Amnesia
Angioedema
Anorexia
Anxiety
Arthralgia
Asthenia
Ataxia
Back pain
Blood glucose fluctuations (in diabetic patients)
Breast enlargement
Bronchitis
Chest pain
Choreo-athetoid movements
Confusion
Convulsions
Cough
Depression
Dizziness
Dry mouth
Dry throat
Dysarthria
Dyskinesia
Dyspepsia
Dyspnoea
Dystonia
Emotional lability
Eosinophilia
Erythema multiforme
Facial oedema
Falls
Fatigue
Fever
Fractures
Gait abnormality
Gastrointestinal disorder
Gingivitis
Gynaecomastia
Hallucinations
Headache
Hepatitis
Hostility
Hypaesthesia
Hyperkinesia
Hypertension
Hypokinesia
Impaired co-ordination
Impotence
Increased appetite
Infection
Influenza-like syndrome
Insomnia
Jaundice
Leucopenia
Loss of consciousness (transient)
Lymphadenopathy
Malaise
Myalgia
Myoclonus
Nervousness
Nystagmus
Oedema
Otitis media
Pain - generalised
Palpitations
Pancreatitis
Paraesthesia
Peripheral oedema
Pharyngitis
Pneumonia
Pruritus
Reflex disorders
Respiratory depression
Respiratory tract infection
Rhinitis
Sexual dysfunction
Skin reactions
Somnolence
Stevens-Johnson syndrome
Thrombocytopenia
Tinnitus
Tremor
Twitching
Urinary incontinence
Urinary tract infections
Vasodilatation
Vertigo
Viral infection
Visual disturbances
Weight gain
White blood cell count decreased
Withdrawal symptoms
Effects on Laboratory Tests
False positive readings have been reported with the urine protein dipstick test. It is recommended that different analytical procedures such as the Biuret method, turbidimetric or dye-binding methods are used.
Overdosage
It is strongly recommended that the UK National Poisons Information Service be consulted on cases of suspected or actual overdose where there is doubt over the degree of risk or about appropriate management.
The following number will direct the caller to the relevant local centre (0844) 892 0111
Information may be obtained if you have access to ToxBase the primary clinical toxicology database of the National Poisons Information Service. This is available via password on the internet ( www.toxbase.org ) or if this is unavailable at the backup site ( www.toxbasebackup.org ).
Further Information
Last Full Review Date: June 2014
Reference Sources
Drugs During Pregnancy and Lactation: Treatment Options and Risk Assessment, 3rd edition (2015) ed. Schaefer, C., Peters, P. and Miller, R. Elsevier, London.
Drugs in Pregnancy and Lactation: A Reference Guide to Fetal and Neonatal Risk, 10th edition (2015) ed. Briggs, G., Freeman, R. Wolters Kluwer Health, Philadelphia.
Martindale: The Complete Drug Reference, 37th edition (2011) ed. Sweetman, S. Pharmaceutical Press, London.
Summary of Product Characteristics: Gabapentin 50mg/ml oral solution. Rosemont Pharmaceuticals Ltd. Revised October 2012.
Summary of Product Characteristics: Neurontin capsules and tablets. Pfizer Limited. Revised September 2018
Summary of Product Characteristics: Segosana capsules and tablets. Zentiva. Revised March 2014
Clinical Knowledge Summaries - Neuropathic pain - drug treatment
Pregnancy and Breastfeeding
Available at: https://cks.nice.org.uk/neuropathic-pain-drug-treatment#!prescribinginfosub:12
Last accessed: 18 June, 2014.
Clinical Knowledge Summaries - Pre-conception - advice and management - Management
How do I manage a woman with epilepsy who wishes to become pregnant?
Available at: https://cks.nice.org.uk/pre-conception-advice-and-management#!scenariorecommendation:17
Last accessed: 18 June, 2014.
Clinical Knowledge Summaries - Epilepsy - Management
Scenario: Epilepsy - Pregnancy planning and pregnancy
Available at: https://cks.nice.org.uk/epilepsy#!scenariorecommendation:8
Last accessed: 18 June, 2014.
Clinical Knowledge Summaries - Epilepsy - Management
Risk from use of AEDs during pregnancy
Available at: https://cks.nice.org.uk/epilepsy#!scenariorecommendation:7
Last accessed: 18 June, 2014.
MHRA Drug Safety Update Vol 2, Issue 1, August 2008
Antiepileptics: risk of suicidal thoughts and behaviour
Available at: www.mhra.gov.uk/Publications/Safetyguidance/DrugSafetyUpdate/CON023078
Last accessed: 18 June, 2014.
MHRA Drug Safety Update Vol 11, Issue 3, October 2017
Gabapentin (Neurontin): risk of severe respiratory depression
Available at: https://www.gov.uk/drug-safety-update/gabapentin-neurontin-risk-of-severe-respiratory-depression
Last accessed: 23 October, 2017
MHRA Drug Safety Update April 2019
Available at: https://www.mhra.gov.uk
Last accessed: 03 May 2019
NICE clinical guideline 20 - The epilepsies, October 2004
Available at: www.nice.org.uk/nicemedia/pdf/CG020NICEguideline.pdf
Last accessed: 18 June, 2014.
NICE Evidence Services Available at: www.nice.org.uk Last accessed: 06 March, 2018
US National Library of Medicine. Toxicology Data Network. Drugs and Lactation Database (LactMed). Record 358 - Gabapentin
Available at: https://toxnet.nlm.nih.gov/cgi-bin/sis/htmlgen?LACT
Gabapentin. Last revised: 31 October 2018.
Last accessed: 18 June, 2014.
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