Mirror Health
Medication Guide
Lamotrigine (Lamictal)
Anticonvulsant · Mood StabilizerA daily medication used for long-term mood stability in bipolar I disorder. Here's what to expect while taking it.
How it's taken
Lamotrigine is raised slowly, one small step at a time. When it's your only mood medication, a common schedule is 25 mg once daily for two weeks, then 50 mg daily for two weeks, then 100 mg in week five, reaching a usual target of 200 mg daily around week six. Your exact schedule depends on the other medicines you take.
Take it at about the same time each day, with or without food. It can be taken once daily or split into two doses. It's a daily maintenance medicine — it works by keeping a steady level in your body, not by taking extra when symptoms flare.
The slow step-up isn't optional — it's the main way the risk of a serious rash is kept low (see the boxed warning). Don't speed it up or restart at a higher dose on your own. If you also take valproate (Depakote), the dose is cut roughly in half; with certain seizure medicines like carbamazepine, it may need to be higher.
How long until it works
Lamotrigine is a maintenance medication — it's meant to reduce future mood episodes over time rather than lift symptoms right away. Because the dose is raised gradually, it usually takes about 6 weeks to reach the target, and the steadying benefit builds over the weeks that follow.
It isn't a fast-acting or as-needed medicine, and it's not used to treat an episode of mania in the moment. Keep taking it as prescribed and check in with your prescriber about how it's going rather than stopping on your own.
If you miss a dose
Take it as soon as you remember that same day. If it's nearly time for your next dose, skip the one you missed — don't take two to catch up.
If you've missed several days in a row, don't just restart your usual dose. After a longer gap, your body may need the dose built back up slowly again to keep the rash risk low — contact your prescriber for how to restart safely.
Common side effects
Many of these are mild and often ease as your body adjusts:
- Dizziness or headache
- Blurred or double vision
- Nausea, vomiting, or stomach upset
- Sleepiness, or trouble sleeping
- Tremor or unsteadiness
- Dry mouth, back pain, tiredness, or a runny nose
A mild rash can also happen. Because it isn't possible to tell early on which rashes are harmless, let your prescriber know about any rash promptly — see below.
Serious side effects
These are uncommon, but contact your prescriber promptly — or seek urgent care for severe symptoms:
- Any skin rash — especially with fever, swollen glands, blistering or peeling skin, or sores in the mouth, eyes, or genitals. Treat this as urgent (see the boxed warning).
- Signs of a whole-body reaction — fever, swollen lymph nodes, facial swelling, or feeling very unwell
- Blood problems — unusual bruising or bleeding, paleness, or repeated infections and fevers
- Meningitis-like irritation — headache with fever, stiff neck, nausea, or sensitivity to light
- New or worsening depression, agitation, or thoughts of self-harm
- Allergic reaction — swelling or trouble breathing → call 911
Serious skin rashes
Lamotrigine can cause rare but life-threatening skin reactions, including Stevens-Johnson syndrome and toxic epidermal necrolysis. The risk is higher when the starting dose is too high, when the dose is raised too quickly, or when it's combined with valproate.
Most serious rashes appear in the first 2 to 8 weeks. Because there's no reliable way to tell early on which rashes will turn dangerous, contact your prescriber at the very first sign of any rash — don't wait to see if it passes. This is exactly why the dose is increased so slowly.
Stopping the medication
Don't stop suddenly. When it's time to stop, your prescriber will lower the dose gradually — usually over at least two weeks — since stopping abruptly can let mood symptoms return (and, in people who take it for seizures, can trigger seizures). The one exception is a serious rash or reaction, which may need the medicine stopped right away under your prescriber's guidance.
Interactions & cautions
- Valproate (Depakote, Depakene): raises lamotrigine levels and the risk of rash — the lamotrigine dose is deliberately cut about in half when they're taken together.
- Certain seizure medicines (carbamazepine, phenytoin, phenobarbital, primidone) and rifampin lower lamotrigine levels, so a higher dose may be needed.
- Estrogen-containing birth control or hormone therapy can lower lamotrigine levels. Starting it, stopping it, or the placebo week of the pill can shift your levels — tell your prescriber so the dose can be adjusted.
- Tell your prescriber if you're pregnant, planning a pregnancy, or breastfeeding — there's a small increased risk of cleft lip or palate, so you'll weigh the options together.
- Alcohol and other sedating substances can add to dizziness or drowsiness. Don't drive until you know how it affects you.