Lamotrigine (Lamictal)

What is lamotrigine?

Lamotrigine is known as Lamictal in the United States, the UK, and Japan alike (ラミクタール on Japanese packaging, with generics widely available). It's a mood stabiliser that is also a long-established epilepsy medicine: it steadies overexcitable brain signalling, and in bipolar disorder its job is keeping mood episodes from coming back.

How is it different from other mood medicines?

• The prevention specialist: its strength is keeping bipolar episodes, especially the depressive ones, from returning
• One of the mood stabilisers most often chosen around pregnancy planning, with large registries behind that practice
• Light to live with day to day: not sedating for most people, and weight-neutral
• The shortest rule-out list on this site: a single formal contraindication

What is it used for in Japan?

• Preventing the return of mood episodes in bipolar disorder
• Several types of epilepsy

How does it help?

By steadying overexcitable signalling, it makes the next mood episode less likely; it's protection, not a rescue medicine. Because of that, the payoff is measured over months of stability rather than days, and it's built up slowly on purpose (see below).

What should I tell my doctor before starting?

Only one situation rules it out entirely:

• A past allergic reaction to lamotrigine

And tell your doctor first if any of these apply; these usually just need adjustments or a closer eye:

• Valproate (Depakene), or epilepsy medicines like carbamazepine or phenytoin; these change lamotrigine's level, and the build-up schedule is adjusted around them
• Any previous serious skin reaction to any medicine
• Kidney or liver problems
• Pregnant, planning to be, or breastfeeding (see the section below)

How do I take it, and what if I miss a dose?

Lamotrigine is taken once or twice a day, and it is built up slowly, week by week, on a fixed schedule. The slow start isn't caution for its own sake: going up too fast is what raises the risk of the rash below, so the schedule is the safety system. Don't speed it up, even if you feel nothing yet.

• If you miss a dose: take it when you remember, unless the next dose is close; in that case just skip. Never take a double dose to catch up
• If you've missed several days in a row, don't just restart at your usual dose; call us first. After a break, the slow build-up may need to start again

What side effects should I expect?

Most are mild and settle as your body adjusts, and many can be eased with a counter-medicine if they persist. Not everyone gets them; the rough figures below just give a sense of how common each one is.

• Drowsiness (around 15%)
• Mild rash (around 5%): most rashes on lamotrigine are harmless, but with this medicine, every rash gets checked (see below)
• Dizziness
• Headache
• Double or blurred vision, in some people
• Nausea

If anything is bothering you, tell your doctor; there's often a way to adjust.

Finally, the one thing everyone starting lamotrigine should know, told straight:

• Very rarely, lamotrigine can cause a serious skin reaction, and this is exactly why the slow build-up schedule exists and works. The rule is simple: a rash plus any of fever, sore throat, mouth sores, or red eyes, especially in the first weeks, means contact us straight away and don't take the next dose until we've spoken. Caught at the rash stage, it's managed by stopping the medicine; the serious forms are rare, and rarer still when the schedule is followed

Will I become dependent? How do I stop safely?

No; lamotrigine isn't habit-forming. Stopping is about protection rather than withdrawal: coming off removes the shield against the next episode, so the decision and the pace are planned with your doctor, usually stepping down gradually.

Can I drive while taking it?

For bipolar disorder, the Japanese label advises against driving while taking it. Lamotrigine can cause drowsiness or dizziness in some people, and for the bipolar indication the prescribing information here instructs that patients on it shouldn't drive or operate dangerous machinery. Discuss your own situation with your doctor.

What about pregnancy and breastfeeding?

Around pregnancy, lamotrigine is one of the mood stabilisers doctors most often keep. Large international registries haven't shown a clear rise in major malformations, which is why it's frequently the medicine of choice when a pregnancy is planned; blood levels can drift during pregnancy, so doses are watched. Never stop on your own on learning you're pregnant.

Breastfeeding is the more cautious conversation with this particular medicine: unusually much passes into milk (an infant's level can reach up to about half of the mother's), so the Japanese label advises avoiding breastfeeding, and any exception is a carefully monitored, individual decision. Our guides to medication in pregnancy and medication while breastfeeding cover the details.