Lamotrigine (Lamictal)

What it treats

Lamotrigine is approved by the U.S. Food and Drug Administration for the maintenance treatment of bipolar I disorder. In that role it helps delay mood episodes. It is particularly useful for preventing the depressive episodes of bipolar disorder, which is where it stands out from some other mood stabilizers.

It is also an anticonvulsant, and it is approved to treat certain seizure disorders. This guide focuses on its use in bipolar disorder.

How it works

Lamotrigine is an anticonvulsant that also stabilizes mood. It calms excessive nerve signaling, in part by reducing the release of glutamate, an excitatory chemical messenger that nerve cells use to pass signals.

The full picture of how it stabilizes mood isn't known. What is clear in practice is that it is better at preventing the depressive side of bipolar disorder than at treating acute mania.

What to expect

Lamotrigine works differently from a medication with a fast, obvious day-to-day effect. It must be started at a low dose and increased very slowly over several weeks, so reaching an effective dose takes time.

It is a maintenance medication. It works over the longer term to prevent episodes rather than producing a quick change you feel within days. The slow start can be frustrating, but it is built into how the medication is used safely.

Common side effects

Most people tolerate lamotrigine well. The common side effects include:

• Headache.
• Dizziness.
• Nausea.
• Sleepiness, or for some people trouble sleeping.
• Blurred or double vision.
• Tremor.

A skin rash can also occur. A rash needs attention rather than waiting to see if it settles. See the warnings below.

Serious side effects and warnings

Serious problems are uncommon, but a few are important to understand.

Boxed warning. Lamotrigine carries an FDA boxed warning about rare but serious, potentially life-threatening skin reactions. These include Stevens-Johnson syndrome and toxic epidermal necrolysis, in which the skin blisters and peels, and a severe reaction called DRESS that affects the skin and internal organs. The risk is highest in the first weeks of treatment, and it is increased by starting at too high a dose or increasing the dose too quickly. This is exactly why lamotrigine is started low and increased very slowly. Any new rash, especially in the first weeks or when it comes with fever or feeling unwell, should be reported to a prescriber promptly.

• Suicidal thoughts. Like other anticonvulsants, lamotrigine carries a warning about a possible small increase in suicidal thoughts. Any new or worsening thoughts of self-harm should prompt contact with the prescriber.
• Interaction with valproate. Combining lamotrigine with valproate raises lamotrigine levels and increases the rash risk. When the two are used together, the dose increases are made even more slowly.
• Mood switch. As with other treatments for bipolar disorder, a switch in mood is possible. Report any new agitation or shift toward mania.

Sexual side effects

Lamotrigine is not a notable cause of sexual side effects. That is an advantage over some other psychiatric medications, which more often affect sex drive, arousal, or orgasm.

Weight, appetite, and sleep

Lamotrigine is relatively weight-neutral. That sets it apart from lithium and valproate, which can both cause weight gain, and it is one reason some people and prescribers favor it.

Its effect on sleep can go either way. It causes trouble sleeping for some people and sleepiness for others. If sleep changes are bothersome, that is worth raising with the prescriber.

Starting and dosing basics

This section is general background, not a dosing instruction for any individual. The right dose and schedule are decisions for a prescriber.

Lamotrigine comes as tablets, chewable tablets, and orally disintegrating tablets that dissolve in the mouth. It is started at a low dose and increased very gradually over several weeks. The exact schedule depends on other medications a person takes. Valproate slows the increases further, while certain other drugs speed lamotrigine's clearance and may call for a different schedule. Starter kits are often used to guide the slow increase week by week.

Missed doses and interactions

Missing several doses in a row matters with lamotrigine. Because the rash risk is tied to how quickly the dose rises, restarting after a gap may mean building the dose up slowly again rather than resuming the full dose. Missed doses should be discussed with the prescriber rather than handled by guessing.

Several interactions matter. Valproate raises lamotrigine levels. Carbamazepine and some other drugs lower them. Hormonal contraceptives can also lower lamotrigine levels, which can affect how well it works. Give every prescriber and pharmacist a full list of your medications and supplements, including over-the-counter ones.

Stopping and tapering

Stopping lamotrigine should be gradual and planned with a prescriber. An abrupt stop can affect mood stability, so a step-down over time is the safer approach. Deciding to stop because you feel well is understandable, but it is still worth doing slowly and with guidance.

Pregnancy and breastfeeding

This is firmly a clinician decision. Lamotrigine is one of the mood stabilizers more often considered usable in pregnancy, compared with valproate, which is generally avoided. Even so, the decision belongs with a clinician who knows the person's situation. Anyone who is pregnant, planning a pregnancy, or breastfeeding should talk it through with their prescriber so the specific risks and benefits can be weighed.

Cost and generic availability

Lamotrigine has been available as a generic for many years and is inexpensive. The brand name is Lamictal. Brand Lamictal and generic lamotrigine contain the same active medication and work the same way.

Common questions

Why is lamotrigine started so slowly? The slow start lowers the risk of a rare but serious skin reaction. That risk is highest early on and is increased by starting too high or increasing too fast, so building the dose up gradually is a safety step.

What should I do if I get a rash? Contact your prescriber promptly, especially if the rash is in the first weeks of treatment or comes with fever or feeling unwell. Do not just wait to see if it clears.

Does it cause weight gain? Lamotrigine is relatively weight-neutral, which sets it apart from lithium and valproate.

What happens if I miss several doses? A gap matters with lamotrigine. After missing several doses, the dose may need to be built up slowly again rather than resumed in full, so check with your prescriber.

Is it addictive? No. Lamotrigine doesn't cause cravings or compulsive use. The body does adjust to it, which is why stopping should be gradual.

Questions to ask your prescriber

• What are we hoping this treats, and how will we know it's working?
• What does my dose schedule look like over the coming weeks?
• Which rash warning signs should make me call you right away?
• How long should I plan to take it?
• If we decide to stop it later, how would we do that safely?

Sources

This guide draws on current prescribing information and public health references. It is reviewed for clinical accuracy and updated as guidance changes.

• U.S. Food and Drug Administration. Lamotrigine (Lamictal) prescribing information.
• MedlinePlus, U.S. National Library of Medicine. Lamotrigine.
• National Institute of Mental Health. Mental health medications.
• American Psychiatric Association. Practice guideline for the treatment of patients with bipolar disorder.