lamotrigine

Mood stabilizer • Brands: Lamictal

Last reviewed: 2025-09-26

General information

Class: Mood stabilizer
Common US brands: Lamictal
Typical dose range: Standard regimen (no valproate or strong inducers): 25 mg once daily for weeks 1–2, 50 mg once daily weeks 3–4, 100 mg once daily week 5, then 200 mg/day from week 6 onward with optional increases to 300–400 mg based on response.
Therapeutic drug monitoring not routinely recommended.
Last reviewed: 2025-09-26

Dosing & forms

Forms/strengths: Immediate-release tablets 25–200 mg with branded titration starter packs that map the six-week escalation.; Chewable/dispersible 2–25 mg and orally disintegrating tablets 25–200 mg for flexible dosing or adherence support.; Extended-release tablets 25–300 mg administered once daily.
Frequency: Standard regimen (no valproate or strong inducers): 25 mg once daily for weeks 1–2, 50 mg once daily weeks 3–4, 100 mg once daily week 5, then 200 mg/day from week 6 onward with optional increases to 300–400 mg based on response.
Typical range: Standard regimen (no valproate or strong inducers): 25 mg once daily for weeks 1–2, 50 mg once daily weeks 3–4, 100 mg once daily week 5, then 200 mg/day from week 6 onward with optional increases to 300–400 mg based on response.

Mechanism (brief)

Voltage-gated sodium channel blocker that reduces glutamate release and stabilizes neuronal membranes; mood stabilizer with antidepressant properties.

Metabolism & Half‑life

Metabolism: UGT1A4, UGT2B7
Half‑life: Single-dose mean 25 h

Therapeutic Drug Monitoring (TDM)

Recommended: No

View labelExact

Sources

Lamotrigine tablets — Prescribing Information — DailyMed (2024)
The CANMAT and ISBD Guidelines for the Management of Patients With Bipolar Disorder: 2021 Update — Bipolar Disorders (2021)
Bipolar disorder: assessment and management (NICE guideline CG185) — National Institute for Health and Care Excellence (2020)
Lamotrigine augmentation in treatment-resistant bipolar depression: a STEP-BD randomized trial — American Journal of Psychiatry (2006)
Lamotrigine in mood disorders: a systematic review — Annals of Clinical Psychiatry (2018)
AGNP Consensus Guidelines for Therapeutic Drug Monitoring in Neuropsychopharmacology — Pharmacopsychiatry (2018)

General information

Class: Mood stabilizer

Common US brands: Lamictal

Typical dose range: Standard regimen (no valproate or strong inducers): 25 mg once daily for weeks 1–2, 50 mg once daily weeks 3–4, 100 mg once daily week 5, then 200 mg/day from week 6 onward with optional increases to 300–400 mg based on response.

Therapeutic drug monitoring not routinely recommended.

Last reviewed: 2025-09-26

Dosing & forms

Forms/strengths: Immediate-release tablets 25–200 mg with branded titration starter packs that map the six-week escalation.; Chewable/dispersible 2–25 mg and orally disintegrating tablets 25–200 mg for flexible dosing or adherence support.; Extended-release tablets 25–300 mg administered once daily.

Frequency: Standard regimen (no valproate or strong inducers): 25 mg once daily for weeks 1–2, 50 mg once daily weeks 3–4, 100 mg once daily week 5, then 200 mg/day from week 6 onward with optional increases to 300–400 mg based on response.

Typical range: Standard regimen (no valproate or strong inducers): 25 mg once daily for weeks 1–2, 50 mg once daily weeks 3–4, 100 mg once daily week 5, then 200 mg/day from week 6 onward with optional increases to 300–400 mg based on response.