Lamotrigine (Lamictal) for Bipolar Disorder: Uses, Dosage, Rash Risk, and What to Expect
Lamotrigine (brand name Lamictal) is a mood stabilizer FDA-approved to help prevent new mood episodes in bipolar I disorder, and it’s especially valued for preventing the depressive side of bipolar illness. It’s generally well tolerated, usually doesn’t cause weight gain, and doesn’t need routine blood levels. The catch is a rare but serious rash, which is why it has to be started slowly, over about six weeks, and why any new rash needs a call to your prescriber. It isn’t used to treat acute mania.
Anticonvulsant mood stabilizer
200 mg/day, reached over ~6 weeks
Preventing bipolar depression
Not routinely required
What Is Lamotrigine Used For?
- Bipolar I disorder, maintenance. FDA-approved to delay new mood episodes after an acute episode has been treated (bipolar disorder treatment).
- Epilepsy, its original FDA-approved use
- Off-label: bipolar II disorder and bipolar depression, and sometimes added for hard-to-treat depression
Lamotrigine is better at preventing depressive episodes than manic ones, and it isn’t effective for acute mania. People who also need mania protection often take it alongside another medication, such as lithium or an antipsychotic.
How Does Lamotrigine Work?
Lamotrigine calms overactive nerve signaling by blocking certain sodium channels and reducing the release of glutamate, an excitatory chemical messenger. Exactly why this stabilizes mood isn’t fully understood, but the result is steadier mood over time rather than a quick effect.
Lamotrigine Dosage: The Slow Titration
The starting schedule is the single most important thing about lamotrigine. Going faster than recommended raises the risk of serious rash. The schedule depends on your other medications:
| Week | Most people (no valproate or inducers) | With valproate (Depakote) | With carbamazepine or similar inducers |
|---|---|---|---|
| 1–2 | 25 mg daily | 25 mg every other day | 50 mg daily |
| 3–4 | 50 mg daily | 25 mg daily | 100 mg daily (divided) |
| 5 | 100 mg daily | 50 mg daily | 200 mg daily (divided) |
| 6 onward | 200 mg daily (target) | 100 mg daily (target) | 300 mg, then up to 400 mg (divided) |
Source: Lamictal FDA prescribing information, adult bipolar dosing. Your prescriber will give you your exact schedule.
- The usual target is 200 mg a day. Higher doses didn’t add benefit in bipolar trials.
- Valproate roughly doubles lamotrigine levels (its half-life rises from about 26 to about 70 hours), which is why the schedule is halved.
- Missed 5 or more days? Don’t restart at your full dose. Call your prescriber; you’ll likely need to restart the titration.
- Starter kits make the schedule easier to follow.
The Rash Warning: What You Need to Know
Most rashes on lamotrigine are mild and not dangerous, but there’s no reliable way to tell early on which ones will become serious. That’s why the label advises stopping at the first sign of rash unless it’s clearly unrelated. Most serious rashes appear in the first 2 to 8 weeks.
Practical tips some clinicians recommend during the first couple of months include avoiding new soaps, detergents, cosmetics, or foods, and avoiding sunburn, so a new rash is easier to interpret.
Lamotrigine Side Effects
In bipolar trials, the most common side effects (more than 5% of adults) were:
- Nausea
- Insomnia or drowsiness
- Fatigue
- Back or abdominal pain
- Rash (mostly mild)
- Stuffy nose and dry mouth
Higher levels can cause dizziness, unsteadiness, double vision, or blurred vision. Lamotrigine is generally considered weight-neutral and doesn’t typically cause sexual side effects or sedation the way some mood stabilizers do.
Rare but serious risks
- Hemophagocytic lymphohistiocytosis (HLH), a rare immune reaction. Report fever, rash, and swollen glands, especially in the first weeks.
- Aseptic meningitis: headache, fever, stiff neck, and light sensitivity
- Blood count problems and, rarely, heart rhythm effects in people with certain heart conditions
- Suicidal thoughts, a warning shared by all antiepileptic drugs
Interactions and Precautions
- Estrogen-containing birth control pills can cut lamotrigine levels by about half, and levels can rise during the pill-free week. Dose changes are usually needed when starting or stopping them. Progestin-only pills didn’t affect levels.
- Valproate (Depakote) raises lamotrigine levels; carbamazepine, phenytoin, and rifampin lower them.
- Pregnancy: levels typically fall during pregnancy and rise after delivery, so close dose monitoring is needed. Plan pregnancy with your prescriber.
- Stopping: taper over at least 2 weeks unless a rash or other safety issue requires stopping immediately.
Lamotrigine vs. Other Mood Stabilizers
| Lamotrigine | Divalproex (Depakote) | Quetiapine (Seroquel) | |
|---|---|---|---|
| Strongest for | Preventing depression | Treating mania | Mania and bipolar depression |
| Weight gain | Usually none | Common | Common |
| Routine blood tests | Not required | Levels, liver, blood counts | Glucose and lipids |
| Key caution | Rash; slow start | Liver, pregnancy | Sedation, metabolic effects |
See our guides to divalproex (Depakote) and quetiapine (Seroquel).
How We Approach Lamotrigine at Samz Mental Health
- Confirm the bipolar diagnosis and pattern, since lamotrigine fits depression-predominant bipolar illness best
- Give you a written titration schedule and review your other medications, including birth control and valproate
- Check in during the first 8 weeks, when rash risk is highest, and make it easy to reach us about a rash
- Build a long-term plan through ongoing medication management
Can You Get Lamotrigine Prescribed Online?
Yes. Lamotrigine isn’t a controlled substance and doesn’t require routine blood levels, so it can be started and managed through telehealth when appropriate. Samz Mental Health treats bipolar disorder by video for adults physically located in Texas, New York, Florida, Colorado, Washington, Maryland, New Hampshire, New Mexico, and Iowa.
In-network with Aetna, Cigna, UnitedHealthcare, Optum, and Carelon Behavioral Health. See insurance details.
Frequently Asked Questions About Lamotrigine
What is lamotrigine used for in bipolar disorder?
Preventing new mood episodes in bipolar I disorder, especially depression. It isn’t used for acute mania.
Why does lamotrigine have to be started so slowly?
Fast increases raise the risk of a serious rash, so the dose is built up over about 6 weeks.
How common is the serious lamotrigine rash?
About 0.08% to 0.3% of adults, mostly in the first 2 to 8 weeks. Report any new rash.
What is the target lamotrigine dose for bipolar disorder?
Usually 200 mg a day; 100 mg with valproate; up to 400 mg with carbamazepine.
Does lamotrigine cause weight gain?
It’s generally considered weight-neutral.
Does birth control affect lamotrigine?
Estrogen-containing pills can lower levels by about half, so doses often need adjusting.
What if I miss several doses of lamotrigine?
After about 5 days off, call your prescriber before restarting; you may need to retitrate.
Can I get lamotrigine prescribed online?
Yes, after a telehealth evaluation. Samz Mental Health treats bipolar disorder by video in nine states.
Talk to a Provider About Bipolar Treatment
Book a video evaluation with a board-certified psychiatric nurse practitioner. Same-day appointments available. No referral needed.
References
- Lamictal (lamotrigine) prescribing information. Drugs.com professional label; also on DailyMed.
- Depakote (divalproex) prescribing information, lamotrigine interaction. Drugs.com professional label.
Medical disclaimer: This page is for education and is not a substitute for a personal medical evaluation. Don’t start, stop, or change any medication without talking to your prescriber. If you’re in crisis or thinking about harming yourself, call or text 988 (Suicide & Crisis Lifeline) or call 911.