Lamotrigine: what it treats, how to take it, side effects
Last updated September 3, 2026.
Lamotrigine is an anticonvulsant that decreases abnormal electrical activity in the brain - and the one whose rash warning dictates everything about how it is started. You may know it as Lamictal. It treats epilepsy and keeps bipolar I episodes apart, and it works only because the dose climbs slowly.
What does it treat?
Certain seizure types in epilepsy and Lennox-Gastaut syndrome (alone or with other medications, depending on the form), and bipolar I disorder - where it increases the time between episodes of depression, mania, and other abnormal moods. It does not treat a mood episode already underway; other medications handle that.
How do you take it?
Exactly as directed, once or twice a day with or without food (extended-release once daily) - and the starter kit exists for a reason. Your doctor starts low and increases no more than once every 1 to 2 weeks; a higher starting dose or faster climb raises the risk of the serious rash. Tablets and extended-release tablets are swallowed whole; chewable tablets can be chewed or dissolved in a teaspoon of water or diluted juice; the orally disintegrating tablet dissolves on your tongue. It may take several weeks to feel the full benefit. Never stop suddenly - seizures can follow - and if you stop for any reason, do not restart without your doctor: the clock on the rash risk resets. Missed dose: take it when you remember unless the next one is close; never double up.
Side effects to know
- Common: loss of balance or coordination, double or blurred vision, uncontrollable eye movements, difficulty thinking or speaking, headache, drowsiness, dizziness, diarrhea, constipation, loss of appetite and weight loss, heartburn, nausea, vomiting, dry mouth, stomach, back, or joint pain, menstrual changes, and uncontrollable shaking.
- Serious - the boxed warning: rashes, including ones requiring hospitalization, causing permanent disability, or death, usually in the first 2 to 8 weeks but possible anytime. Call your doctor immediately for any rash, blistering or peeling skin, hives, itching, or painful sores in the mouth or around the eyes. Taking valproate (valproic acid, divalproex) raises the risk. Also serious: facial or throat swelling with trouble breathing; seizures that are more frequent, longer, or different; meningitis signs (headache, fever, stiff neck, light sensitivity, confusion, drowsiness); unusual bleeding or bruising; and the multi-organ reaction of fever, rash, swollen lymph nodes, yellowing skin or eyes, abdominal pain, painful or bloody urination, chest pain, or muscle weakness.
Who should not take it?
Anyone who has ever developed a rash on lamotrigine or another epilepsy medication - that history changes the risk math entirely. Valproate use must be disclosed (it roughly doubles the rash risk). Hormonal birth control users: lamotrigine may decrease contraceptive effectiveness, so another method is needed. Flag liver, kidney, or heart problems, depression, and any past suicidal thoughts. Pregnancy and breastfeeding need a direct call with your doctor. One practical warning from MedlinePlus: lamotrigine's brand name resembles other medications - compare your tablets to the pictures in the patient information sheet every refill, and ask the pharmacist if anything looks different.
When is it an emergency?
Trouble breathing or swallowing, facial or throat swelling, and blistering or peeling skin are a 911 call. Any rash while on lamotrigine means calling your doctor immediately - same day. Fever with stiff neck and light sensitivity, or yellowing skin with swollen glands, mean immediate care. For an overdose, call Poison Control at 1-800-222-1222. Pymander's escalation routing is built and tested specifically for this class of decision; see the safety architecture working paper.
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Common questions
Why does lamotrigine take so long to start?
The rash. A higher starting dose or faster increases raise the risk of serious rashes, per MedlinePlus - so doctors start low and increase no more than once every 1 to 2 weeks, and the first 5 weeks often come in a starter kit that lays out each day's dose. The slow ramp is the safety feature, not caution theater.
What does the lamotrigine rash look like?
Any rash counts - that is the point. MedlinePlus says call your doctor immediately for rash, blistering or peeling skin, hives, itching, or painful sores in the mouth or around the eyes. Serious rashes usually develop in the first 2 to 8 weeks but can appear anytime. Do not self-triage whether it looks bad enough - the call is the protocol.
Does lamotrigine interact with birth control?
Yes. MedlinePlus says lamotrigine may decrease the effectiveness of hormonal contraceptives - pills, patches, rings, injections - so another method of contraception is needed while taking it. Talk to your doctor about options before starting, not after.
Why did my doctor ask if I take valproate?
Because it changes the risk. MedlinePlus says taking valproic acid (Depakene) or divalproex (Depakote) with lamotrigine increases the risk of a serious rash, so the titration schedule and doses differ when valproate is in the mix. Never start or stop either drug without both prescribers knowing.
I stopped lamotrigine for a week - can I just restart it?
No. MedlinePlus says if you stop taking lamotrigine for any reason, do not start taking it again without talking to your doctor. The rash risk ties to how the drug is started, so restarting at your old dose after a gap reopens that risk - your doctor may restart the titration from the beginning.
Can I drink alcohol while taking lamotrigine?
Neither the label nor MedlinePlus lists a specific alcohol interaction for lamotrigine. The drowsiness and dizziness it can cause stack with alcohol, and for the bipolar indication alcohol works against mood stability on its own - worth a direct conversation with your prescriber.