What Is Lamotrigine? Uses, Dosage, and What You Need to Know in 2026

Lamotrigine is one of the most widely prescribed medications in the United States — the most commonly prescribed mood stabilizer and the 59th most prescribed drug overall in 2023, with more than 10 million prescriptions. It treats two very different conditions: epilepsy and bipolar disorder. If you've been prescribed lamotrigine or a loved one has, this guide gives you the foundational knowledge you need.

What Is Lamotrigine?

Lamotrigine (brand name Lamictal) is an anticonvulsant (anti-seizure) medication that also has proven effectiveness as a mood stabilizer for bipolar disorder. It belongs to the phenyltriazine drug class and is chemically distinct from older anticonvulsants like carbamazepine or valproate. The FDA first approved lamotrigine in 1994, and it is included on the World Health Organization's List of Essential Medicines.

Lamotrigine is available as both brand-name (Lamictal, Subvenite) and generic (lamotrigine) versions. The generic is significantly less expensive and equally effective by FDA standards.

What Conditions Does Lamotrigine Treat?

Lamotrigine has FDA-approved uses and several off-label uses:

Epilepsy (seizure disorders): Approved as an add-on (adjunctive) therapy and for monotherapy in adults 16+ for focal (partial) seizures; as add-on therapy for primary generalized tonic-clonic seizures; and as add-on therapy for seizures in Lennox-Gastaut syndrome in patients 2 and older.

Bipolar I disorder maintenance: Approved to delay the time to occurrence of mood episodes (depression, mania, hypomania, mixed) in adults already being treated for acute mood episodes. Important note: lamotrigine is NOT approved for treating acute manic or depressive episodes — it's for maintenance (prevention) only.

Off-label uses: Major depressive disorder (as add-on to antidepressants), acute bipolar depression, depersonalization-derealization disorder, and others. These are not FDA-approved indications but are supported by clinical evidence and commonly prescribed.

What Forms Does Lamotrigine Come In?

Lamotrigine is available in several formulations:

Immediate-release (IR) tablets: 25 mg, 100 mg, 150 mg, 200 mg. The most commonly prescribed and most widely stocked formulation. Taken 1-2 times daily.

Chewable/dispersible tablets (CD): 2 mg, 5 mg, 25 mg. Can be swallowed whole, chewed, or dissolved in liquid. Useful for patients who have difficulty swallowing, and for the low doses needed during initiation.

Orally disintegrating tablets (ODT): 25 mg, 50 mg, 100 mg, 200 mg. Dissolve on the tongue. Useful for patients who have swallowing difficulties.

Extended-release tablets (XR): 25 mg, 50 mg, 100 mg, 200 mg, 250 mg, 300 mg. Once-daily dosing for adults and children 13+. Approved for focal seizures and primary generalized tonic-clonic seizures.

Oral suspension (Subvenite, 10 mg/mL): Approved by the FDA in September 2025. Designed for young children and patients who cannot swallow tablets. Distribution is still expanding in 2026.

How Is Lamotrigine Dosed?

Lamotrigine must be started at a very low dose and increased slowly over 7-14 weeks. This is not optional — rapid dose escalation significantly increases the risk of serious skin rash (including Stevens-Johnson syndrome). Your prescriber will give you a specific titration schedule.

For epilepsy (adjunctive, adults not on valproate or enzyme inducers): Start 25 mg/day for weeks 1-2, then 50 mg/day for weeks 3-4, then increase by 50 mg/day every 1-2 weeks; typical maintenance 225-375 mg/day in divided doses.

For bipolar I maintenance (adults): Start 25 mg/day for weeks 1-2, then 50 mg/day for weeks 3-4, then 100 mg/day for week 5, then 200 mg/day at week 6 and beyond; target maintenance 200-400 mg/day.

If taking valproate: Valproate doubles lamotrigine blood levels. Your doses must be approximately half of the standard schedule — your prescriber will adjust accordingly.

If taking enzyme inducers (carbamazepine, phenytoin, phenobarbital): These drugs halve lamotrigine levels. Higher doses are needed — your prescriber will adjust.

How to Take Lamotrigine

Take at the same time each day — consistency helps maintain stable blood levels

Can be taken with or without food — but take with food if it causes stomach upset

Do not stop taking lamotrigine suddenly — this can cause seizures or mood destabilization

If you miss a dose, take it as soon as you remember — unless it's almost time for the next dose; never double up

Store at room temperature, away from heat and moisture

Who Should Not Take Lamotrigine?

The only absolute contraindication to lamotrigine is a known hypersensitivity (allergy) to lamotrigine or any ingredient in the formulation. Additional precautions include:

Patients with pre-existing structural or conduction heart defects (see 2021 FDA cardiac arrhythmia warning)

Patients with significant liver disease (dose reduction required for Child-Pugh B or C)

Patients with significant renal impairment (dose reduction may be needed; monitor carefully)

Pregnancy: discuss with your prescriber — lamotrigine levels change significantly during pregnancy and require careful monitoring

Finding Lamotrigine at a Pharmacy Near You

Standard lamotrigine IR tablets are widely stocked at most pharmacies. If you need a less common formulation (ODT, XR, or the new oral suspension), you may need to search a bit. medfinder calls pharmacies on your behalf to find which ones have your specific formulation and dose in stock near you.

See also: How to Save Money on Lamotrigine in 2026 for cost-saving tips.