Lamotrigine for Bipolar Disorder

Lamotrigine (Lamictal) is an anticonvulsant used in bipolar disorder mainly to help prevent future episodes, especially depressive ones. The FDA approves it for maintenance treatment of bipolar I disorder to delay mood episodes in people who have been treated for an acute episode. It is not a treatment for mania. It has to be started slowly because of a rare but serious rash, so it is a medicine for the long game rather than a crisis. This page covers where lamotrigine fits, how starting it works, the interactions that matter, and what to do about missed doses.

What lamotrigine is used for in bipolar disorder

The Lamictal label is specific: maintenance treatment of bipolar I disorder, to delay the time to the next mood episode. Under "limitations of use", it says treatment of acute manic or mixed episodes is not recommended, and that effectiveness in treating acute mood episodes has not been established.

Guidelines place it like this:

• CANMAT/ISBD 2018 lists lamotrigine as a first-line maintenance option for bipolar I and bipolar II, and as a first-line option for acute bipolar I depression.
• For acute bipolar II depression, CANMAT/ISBD 2018 names quetiapine as the only first-line option; lamotrigine's strength in bipolar II is prevention.
• The VA/DoD 2023 guideline strongly recommends lamotrigine to prevent depressive episodes from returning, but suggests against using it alone to prevent mania.
• NICE CG185 says not to offer lamotrigine to treat mania; it may be considered on its own for bipolar depression if the person prefers.

Because it guards the depressive side more than the manic side, lamotrigine is often combined with another medicine in bipolar I. How it compares with the rest of the class is covered in mood stabilizers explained and bipolar disorder medications explained.

Why it is started slowly

Lamotrigine carries an FDA boxed warning for serious skin rashes, including Stevens-Johnson syndrome. Two of the listed risk factors are starting at a higher dose than recommended and increasing faster than recommended. So the dose is built up gradually over several weeks, and the label says the recommended starting dose and increases should not be exceeded. Starter kits exist to make that schedule easier to follow.

This means lamotrigine is not a quick fix. It takes weeks just to reach a typical dose, which is one reason it suits prevention better than an acute crisis.

Most rashes on lamotrigine are not dangerous, but there is no reliable way to tell early on which ones will become serious. Any new rash means a same-day call to the prescriber. The warning signs and what happens next are on lamotrigine rash: warning signs and risks.

Interactions that change the plan

Valproate (Depakote)

Taking lamotrigine with valproate is the first risk factor named in the rash warning. Valproate slows the body's clearance of lamotrigine, so lamotrigine levels run higher and the starting schedule is different. If valproate is later stopped, lamotrigine levels fall and the dose needs adjusting. Make sure every prescriber knows you take both.

Medicines that lower lamotrigine

Carbamazepine, phenytoin, phenobarbital, rifampin and some HIV medicines speed up lamotrigine's clearance. Starting or stopping one of them changes the dose you need.

Estrogen-containing birth control

Some estrogen-containing birth control pills lower lamotrigine levels, and the label says most people starting or stopping them need a dose adjustment. Levels can also rise during the pill-free week. Pregnancy lowers lamotrigine levels too, and they return to pre-pregnancy levels after delivery. Tell your prescriber before you start or stop hormonal birth control, and as soon as you think you may be pregnant. These hormonal factors are discussed in bipolar disorder in women and bipolar disorder and pregnancy.

Missed doses and restarting

Missing a single dose is usually not a crisis; follow the instructions your prescriber or pharmacist gave you, and do not double up. A longer gap is different.

The label says that if lamotrigine has been stopped for long enough to clear the body (more than five half-lives), the starting schedule should be followed again, because jumping straight back to a full dose raises the rash risk. The longer the gap, the more likely a fresh slow start is needed. How long that is depends on your other medicines.

Questions to settle before the first dose

Because the start of treatment carries the most rash risk, it helps to sort out a few things in advance:

• Do I take valproate, carbamazepine or any other medicine that changes the starting schedule?
• Am I using, starting or stopping estrogen-containing birth control, or could I become pregnant?
• Do I have Asian ancestry in which HLA-B*1502 is more common, and does that change the discussion?
• How do I reach the prescriber the same day if a rash appears?
• What should I do if I miss a dose during the build-up?

Having those answers written down before you start makes the first two months, when rash risk is highest, much simpler.

Other warnings on the label

Beyond rash, the current label lists several less common but important risks:

• Other serious reactions: a rare immune overreaction (hemophagocytic lymphohistiocytosis) and reactions affecting the liver or blood. Fever, swollen glands, unusual bruising or yellowing skin need prompt attention, with or without a rash.
• Heart rhythm: in people with known heart problems, lamotrigine may affect heart conduction. Report a fast, slow or pounding heartbeat, chest pain or fainting.
• Aseptic meningitis: headache, fever, stiff neck and nausea need same-day medical care.
• Mood and suicidal thoughts: like other anti-seizure drugs, lamotrigine carries a warning about suicidal thoughts in a very small number of people. Report new or worsening depression, agitation or unusual changes in mood or behavior.
• Look-alike names: lamotrigine has been confused with other drugs at the pharmacy. Check your tablets each time you pick up a refill.

Teens, side effects and stopping

Lamotrigine has no FDA approval for bipolar disorder in anyone under 18. A trial in 301 young people aged 10 to 17 did not establish that it works for bipolar maintenance in that age group, and the rash rate is higher in children and teens than in adults. See bipolar medication for teens.

In the adult bipolar trials, the most common side effects were nausea, trouble sleeping, sleepiness, back pain, tiredness, rash, a stuffy or runny nose, stomach pain and dry mouth.

Do not stop lamotrigine without talking to your prescriber. The Medication Guide warns that stopping suddenly can cause serious problems, and stopping any bipolar maintenance medicine raises the risk of a new episode.

At Willow & Stone

Dr. Stacey Forbes, PMHNP-BC, cares for adults and teens 10 and up with bipolar disorder in Arlington, Texas, and by telehealth in Texas, New Mexico, Florida, Alaska, Arizona, Colorado and Washington. Medication options, including whether lamotrigine fits your pattern of episodes, are discussed at your evaluation. Learn about bipolar disorder treatment at Willow & Stone or browse the bipolar disorder guide.

Common Questions

Sources & Further Reading

• DailyMed: LAMICTAL (lamotrigine) prescribing information and Medication Guide (October 2025)
• Yatham LN et al. CANMAT and ISBD 2018 guidelines for the management of patients with bipolar disorder. Bipolar Disord 2018 (PMID 29536616)
• Keramatian K, Chithra NK, Yatham LN. The CANMAT and ISBD guidelines for bipolar disorder: an update of evidence. Focus 2023
• VA/DoD Clinical Practice Guideline for the Management of Bipolar Disorder (Version 2.0, 2023)
• NICE CG185: Bipolar disorder: assessment and management (last updated 2 September 2025)

This article is general education, not a diagnosis or advice for your situation. Do not start, stop, or change a medication without talking to the clinician who prescribes it; stopping a mood stabilizer suddenly can trigger relapse.