Lamotrigine


Concise Prescribing Info
Indications/Uses
Listed in Dosage.
Dosage/Direction for Use
Adult : PO Epilepsy Monotherapy or adjunctive therapy w/o valproate and enzyme-inducing antiepileptics: Initial: 25 mg once daily for 2 wk, then 50 mg once daily for 2 wk. Thereafter, increase by max of 50-100 mg/day every 1-2 wk (immediate-release), or increase by 50 mg/day at wkly interval for 3 wk then increase by 100 mg/day at wkly interval thereafter (extended-release tab). Maintenance: 100-200 mg/day (immediate-release); 300-400 mg/day (extended-release). Adjunctive therapy w/ enzyme-inducing antiepileptics w/o valproate: Initial: 50 mg once daily for 2 wk, then 50 mg bid for 2 wk. Thereafter, increase by max of 100 mg/day every 1-2 wk (immediate-release), or increase by 100 mg/day at wkly interval (extended-release). Maintenance: 200-400 mg/day (immediate-release); 400-600 mg/day (extended-release). Adjunctive therapy w/ valproate: Initial: 25 mg every other day for 2 wk, then 25 mg once daily for 2 wk. Thereafter, increase by max of 25-50 mg/day every 1 to 2 wk (immediate-release), or double the daily dose at wkly interval for 2 wk then increase by 50 mg/day at wkly interval thereafter (extended-release). Maintenance: 100-200 mg/day (immediate-release); 200-250 mg/day (extended-release). Bipolar disorder Monotherapy or adjunctive therapy w/o valproate and enzyme inducing antiepileptics: Initial: 25 mg once daily for 2 wk, then 50 mg/day for 2 wk, then 100 mg/day for 1 wk, then increase to a target dose of 200 mg/day. Adjunctive therapy w/ enzyme-inducing antiepileptics w/o valproate: Initial: 50 mg once daily for 2 wk, then 50 mg bid for 2 wk, then 100 mg bid for 1 wk, then 150 mg bid for 1 wk, then increase to a target dose of 400 mg/day. Adjunctive therapy w/ valproate: 25 mg every other day for 2 wk, then 25 mg once daily for 2 wk, then 50 mg/day for 1 wk, then increase to a target dose of 100 mg/day. Max: 200 mg/day.
Dosage Details
Oral
Bipolar disorder
Adult: Monotherapy or adjunctive therapy w/o valproate and enzyme inducing antiepileptics: Initially, 25 mg once daily for 2 wk, then 50 mg daily in 1 or 2 divided doses for 2 wk, then 100 mg daily in 1 or 2 divided doses for 1 wk, then increase to a target dose of 200 mg daily. Adjunctive therapy w/ enzyme-inducing antiepileptics w/o valproate: Initially, 50 mg once daily for 2 wk, then 50 mg bid for 2 wk, then 100 mg bid for 1 wk, then 150 mg bid for 1 wk, then increase to a target dose of 400 mg daily. Adjunctive therapy w/ valproate: 25 mg every other day for 2 wk, then 25 mg once daily for 2 wk, then 50 mg daily in 1 or 2 divided doses for 1 wk, then increase to a target dose of 100 mg daily. Max: 200 mg daily.

Oral
Epilepsy
Adult: Monotherapy or adjunctive therapy w/o valproate and enzyme-inducing antiepileptics: Initially, 25 mg once daily for 2 wk, then 50 mg once daily for 2 wk. Thereafter, increase by max of 50-100 mg daily every 1-2 wk (immediate-release preparations), or increase by 50 mg daily at wkly interval for 3 wk then increase by 100 mg daily at wkly interval thereafter (extended-release tab). Maintenance: 100-200 mg daily (immediate-release); 300-400 mg daily (extended-release). Adjunctive therapy w/ enzyme-inducing antiepileptics w/o valproate: Initially, 50 mg once daily for 2 wk, then 50 mg bid for 2 wk. Thereafter, increase by max of 100 mg daily every 1-2 wk (immediate-release), or increase by 100 mg daily at wkly interval (extended-release). Maintenance: 200-400 mg daily (immediate-release); 400-600 mg daily (extended-release). Adjunctive therapy w/ valproate: Initially, 25 mg every other day for 2 wk, then 25 mg once daily for 2 wk. Thereafter, increase by max of 25-50 mg daily every 1 to 2 wk (immediate-release), or double the daily dose at wkly interval for 2 wk then increase by 50 mg daily at wkly interval thereafter (extended-release). Maintenance: 100-200 mg daily (immediate-release); 200-250 mg daily (extended-release tab).
Child: 2-12 yr Monotherapy or adjunctive therapy w/o valproate and enzyme-inducing antiepileptics: Initially, 0.3 mg/kg daily for 2 wk, then 0.6 mg/kg daily for 2 wk; thereafter, increase by max of 0.6 mg/kg daily every 1-2 wk. Maintenance: 1-15 mg/kg daily (monotherapy); 1-10 mg/kg daily (adjunct therapy). Doses are given as single or in 2 divided doses Max: 200 mg daily. Adjunctive therapy w/ enzyme-inducing antiepileptics w/o valproate: Initially, 0.6 mg/kg daily in 2 divided doses for 2 wk, then 1.2 mg/kg daily in 2 divided doses for 2 wk; thereafter, increase by max of 1.2 mg/kg every 1-2 wk. Maintenance: 5-15 mg/kg daily. Max: 400 mg/day. Adjunctive therapy w/ valproate: Initially, 0.15 mg/kg once daily for 2 wk, then 0.3 mg/kg once daily for 2 wk; thereafter, increase by max of 0.3 mcg/kg daily every 1-2 wk. Maintenance: 1-5 mg/kg daily. Max: 200 mg daily. >12 yr Same as adult dose. Lamotrigine should not be given if the calculated daily dose is <1 mg.
Renal Impairment
Dosage adjustment may be needed.
Hepatic Impairment
Moderate (Child-Pugh category B): Reduce dose by approx 50%. Severe (Child-Pugh category C): Reduce dose by approx 75%.
Administration
May be taken with or without food.
Contraindications
Hypersensitivity.
Special Precautions
Renal and moderate to severe hepatic impairment. Childn. Pregnancy and lactation. Avoid abrupt dose reduction and withdrawal.
Adverse Reactions
Significant: Rash, aseptic meningitis, blood dyscrasias, CNS depression, suicidal ideation and behaviour.
Nervous: Dizziness, drowsiness, headache, ataxia, tremor, fatigue, weakness, flu-like symptoms, coordination abnormality, anxiety, insomnia, aggression, irritability.
CV: Lymphadenopathy.
GI: Nausea, vomiting, diarrhoea, abdominal pain, dyspepsia, dry mouth.
Resp: Bronchitis, rhinitis, chest pain.
Endocrine: Weight decrease, dysmenorrhoea.
Haematologic: Leucopenia, neutropenia, thrombocytopenia, agranulocytosis.
Musculoskeletal: Arthralgia.
Ophthalmologic: Diplopia, nystagmus.
Dermatologic: Photophobia.
Immunologic: Hypersensitivity reactions, infection.
Others: Fever, pain.
Potentially Fatal: Serious skin rashes, Stevens-Johnson syndrome, toxic epidermal necrolysis. Rarely, multiorgan hypersensitivity reactions; haemophagocytic lymphohistiocytosis (HLH) leading to severe problems with blood cells and body organs (e.g. liver, kidneys, lungs).
Patient Counseling Information
This drug may cause dizziness and drowsiness, if affected do not drive or operate machinery.
MonitoringParameters
Monitor for clinical worsening and suicidality, hypersensitivity reactions (e.g. rash), seizure frequency and duration, signs and symptoms of aseptic meningitis. Monitor hepatic and renal function.
Overdosage
Symptoms: Drowsiness, nausea, vomiting, ataxia, seizures, nystagmus, hypertonicity, coma, resp depression. Management: Supportive treatment. Perform gastric lavage immediately after ingestion. Administer activated charcoal.
Drug Interactions
Increased plasma concentration and risk of severe skin reactions w/ valproate. Decreased plasma concentration w/ carbamazepine, phenytoin, phenobarbital, primidone, rifampicin, lopinavir/ritonavir, atazanavir/ritonavir, hormonal contraceptives.
Action
Description: Lamotrigine is a phenyltriazine anticonvulsant agent. It stabilises presynaptic neuronal membranes by blocking voltage sensitive Na channels, subsequently inhibiting the release of excitatory amino acid neurotransmitters (e.g. glutamate, aspartate) which are involved in the generation and spread of epileptic seizures. Its mechanism of action in bipolar disorder is still unknown.
Pharmacokinetics:
Absorption: Rapidly absorbed from the GI tract. Bioavailability: 98% (immediate release. Time to peak plasma concentration: Approx 1-5 hr (immediate release); 4-11 hr (extended-release).
Distribution: Widely distributed in the body. Enters breast milk. Volume of distribution: 1.1 L/kg. Plasma protein binding: Approx 55%, mainly to albumin.
Metabolism: Metabolised in the liver via glucuronidation.
Excretion: Mainly via urine (94%, approx 90% as inactive glucuronide conjugates, approx 10% as unchanged drug); faeces (2%). Elimination half-life: 24-35 hr.
Chemical Structure

Chemical Structure Image
Lamotrigine

Source: National Center for Biotechnology Information. PubChem Database. Lamotrigine, CID=3878, https://pubchem.ncbi.nlm.nih.gov/compound/Lamotrigine (accessed on Jan. 22, 2020)

Storage
Store between 15-30°C. Protect from light and moisture.
ATC Classification
N03AX09 - lamotrigine ; Belongs to the class of other antiepileptics.
References
Anon. Lamotrigine. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 18/07/2017.

Buckingham R (ed). Lamotrigine. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 18/07/2017.

Joint Formulary Committee. Lamotrigine. British National Formulary [online]. London. BMJ Group and Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 18/07/2017.

Lamotrigine Extended Release Tablet (Par Pharmaceutical Inc). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 18/07/2017.

McEvoy GK, Snow EK, Miller J et al (eds). Lamotrigine. AHFS Drug Information (AHFS DI) [online]. American Society of Health-System Pharmacists (ASHP). https://www.medicinescomplete.com. Accessed 18/07/2017.

Disclaimer: This information is independently developed by MIMS based on Lamotrigine from various references and is provided for your reference only. Therapeutic uses, prescribing information and product availability may vary between countries. Please refer to MIMS Product Monographs for specific and locally approved prescribing information. Although great effort has been made to ensure content accuracy, MIMS shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2020 MIMS. All rights reserved. Powered by MIMS.com
  • Apo-Lamotrigine
  • Lamotrix
  • PMS-Lamotrigine
Register or sign in to continue
Asia's one-stop resource for medical news, clinical reference and education
Sign up for free
Already a member? Sign in