Lamotrigine (Lamictal)

What lamotrigine is

Lamotrigine is a medication sold under the brand name Lamictal. It works by calming overactive electrical signaling between nerve cells, partly by steadying the channels that carry those signals. In mental health it is used mainly to help keep mood steady over time, and it is often chosen because many people tolerate it well, without much in the way of weight gain or sedation. It is started slowly and built up step by step, for an important safety reason described below.

What it treats

Your clinician might suggest lamotrigine for one of these, among other possible off-label uses:

• Bipolar disorder, especially to help keep mood steady over the long run and to protect against the low, depressive side
• Depression, in some situations, as part of a broader plan

Whether it is a good fit depends on several factors, including your history and what you are working on. As with everything in psychiatry, that is decided case by case.

How it works

Honestly, no one knows with complete certainty how lamotrigine produces its benefit. What robust research supports is that it quiets overactive electrical signaling in the brain, which seems to help smooth out the swings that come with mood episodes. The biology is only part of the picture: how much a medication helps, and how it feels, is individual. Two people on the same medication can have very different experiences.

How to take it

There is no single right way to take lamotrigine, but one thing is fairly consistent: it is started at a low dose and increased slowly, usually over several weeks. That slow build is not a delay for its own sake; it is the main way we lower the risk of a serious rash. The plan you and your clinician make together is the one to follow, not a number you read online. A few points matter here:

• Follow the step-up schedule closely, and do not jump ahead or restart at a higher dose after a gap without checking first. If you miss several days in a row, ask your clinician before resuming, because the slow build may need to start again.
• If you miss a single dose, ask your clinician or pharmacist what to do rather than doubling up.
• Tell your clinician about other medicines, including birth control and valproate, since some change how much lamotrigine is in your system. The section on other medicines below covers the two that come up most.
• Try not to stop on your own, and do not stop suddenly. Coming off lamotrigine is done gradually. Your clinician can guide any change.

What to expect

This varies from person to person. Because the dose climbs slowly, the full benefit can take a few weeks or more to arrive, while any side effects, if they happen, tend to show up earlier. The slow start is worth the patience. If nothing has shifted after a fair trial at a full dose, that is useful information, not a dead end, and there are other options. As always, this is case by case.

Side effects

Not everyone gets side effects, and many that do happen ease over the first weeks. The lists below are possibilities, not certainties.

Possible more common side effects:

• Headache, dizziness, or feeling unsteady
• Blurred or double vision
• Drowsiness or trouble sleeping
• Nausea or upset stomach
• Trouble concentrating

If any of these stick around or bother you, they are worth raising. Send a non-urgent message through the patient portal or bring it up at your next visit; often a small change helps.

Less common, but concerning side effects that could require emergency care:

• A spreading skin rash, blistering or peeling skin, or sores in the mouth, eyes, or nose. This is the one to take seriously: lamotrigine can rarely cause a severe rash that needs hospital care, and the risk is highest in the first weeks. Do not wait it out.
• A rash together with fever, swollen glands, or feeling generally unwell
• Swelling of the face, lips, tongue, or throat, or trouble breathing
• Unusual bleeding or bruising, or signs of infection like a fever and sore throat
• Any new or worsening thoughts of harming yourself

For any of these, use the help options at the top of this page: call 911 or go to the nearest emergency department for a medical emergency or severe reaction, or call or text 988 for a mental health crisis.

What to do if you get a rash

Most rashes are harmless, and plenty of people on lamotrigine get one that turns out to be nothing. The reason this page keeps returning to it is that no one can tell by looking which rash is the harmless kind. That is why the instruction is the same either way: treat a new rash as a reason to act now rather than watch and wait.

What to do:

• Contact your clinician right away. Do not wait for a routine reply, and do not wait until your next visit. If you can reach us first, we can usually tell you where to go fastest.
• Expect to be told to stop taking it. Standard practice is to stop lamotrigine at the first sign of a rash unless it is clearly coming from something else. Stopping is the cautious move, and it is reversible; waiting is not always.
• Go to an emergency department without waiting if the rash comes with fever, swollen glands, or feeling generally unwell, or if there is blistering or peeling skin, sores in the mouth, eyes, or nose, swelling of the face, lips, or tongue, or any trouble breathing or swallowing.
• Do not start taking it again on your own after stopping for a rash. Restarting is a decision to make together.

Two things that help you judge what is new. First, timing: serious rashes usually appear in the first two to eight weeks after starting or after a dose increase, though they can happen at any point, so the calendar reassures but does not rule anything out. Second, your own baseline: if you already get eczema, psoriasis, or a rash you know well, what we are watching for is one that is new and different from your usual. It is worth telling your clinician up front what your skin normally does, so there is something to compare against.

Other medicines, birth control, and pregnancy

Lamotrigine is not fussy about most medications, but a few interactions genuinely change the plan, and two of them come up often enough to spell out.

Valproate (Depakote, Depakene). Taken together, valproate raises the amount of lamotrigine in your system and increases the risk of a serious rash. This is not a forbidden combination, and it is a useful one for some people. It does mean lamotrigine is started at a lower dose and built up more slowly than usual on purpose. If you are on both, the slower schedule is the safety measure, so it is worth following exactly. Tell your clinician if either medication starts, stops, or changes.

Hormonal birth control. This one runs in both directions, which is why it is easy to miss. Lamotrigine can make hormonal contraceptives less reliable, so if you are taking it to prevent pregnancy, ask about adding or switching to another method. Going the other way, estrogen containing contraceptives lower the amount of lamotrigine in your system, and during a placebo or pill-free week the level rises again, sometimes to roughly double by the end of that week. That swing can show up as dizziness, unsteadiness, or double vision. Most people need a dose adjustment when starting or stopping this kind of contraceptive, including hormone replacement therapy, so tell your clinician before you start, stop, or switch rather than after. Breakthrough bleeding or a change in your usual cycle is also worth mentioning.

Pregnancy. Lamotrigine levels tend to fall during pregnancy and come back up after delivery, which means the dose that was working may stop working partway through and then be too much afterward. This is manageable, and it is manageable best when it is planned. Tell your clinician if you are pregnant or thinking about it, and if you find out you are pregnant, call rather than stopping on your own, because stopping suddenly carries its own risk.

When to reach out, and where

For routine questions, side effects that can wait, or how things are going, send your clinician a message through the patient portal. These are part of your ongoing care and are answered in the normal course of a few business days, so they are best for things that are not urgent. A new rash, though, is worth flagging promptly rather than waiting.

If something feels urgent, you do not need to wait for a reply. The help options at the top of this page are the fastest way to get care: 911 or the nearest emergency department for a medical emergency or severe reaction, or 988 any time for a mental health crisis or thoughts of self-harm.

Questions to ask your clinician

• What are you hoping lamotrigine will help with in my case?
• What does the slow start look like, and how long until we reach a full dose?
• What kind of rash should make me call you or seek care right away, and who should I call first?
• Do any of my other medicines, including birth control and valproate, interact with it?
• If I start, stop, or switch birth control, what do I need to tell you?
• If pregnancy is possible for me, how would we handle it?
• What is the plan if this one turns out not to be the right fit?
• How will we handle stopping it, if and when we get there?