Medication guide

Lithium (Limas)

What is lithium?

In most countries it's prescribed simply as lithium (brand names include Lithobid in the US and Priadel in the UK); in Japan it's Limas (リーマス on Japanese packaging). It's one of the longest-established and most effective mood stabilisers: it calms the highs of mania and helps keep mood even. It works within a fairly narrow range, so the dose is guided by simple blood tests.

How is it different from other mood medicines?

The reference standard: internationally, lithium remains the benchmark long-term treatment in bipolar care
Unusually good evidence on suicide prevention, which few psychiatric medicines can claim
Seventy years of experience: its effects, risks, and monitoring are thoroughly understood
Precision by blood test: the level is measured directly, so dosing is tailored to you rather than guessed

What is it used for in Japan?

In Japan, lithium is approved for bipolar disorder:

Calming mania (the elevated, overactive phase)
Keeping mood stable over the long term

How does it help?

It settles the highs of mania, and over time it helps keep both the highs and the lows from coming back; it supports the depressed side of bipolar disorder too. The dose is fine-tuned with blood tests so there's enough to work without too much; that balance is what keeps it both effective and safe.

What should I tell my doctor before starting?

A few situations rule it out entirely; your doctor will choose something else if any of these apply:

Epilepsy or a known brain-wave (EEG) abnormality
A serious heart condition
A state where lithium builds up easily: significant kidney problems, being severely run-down or dehydrated, illness with fever, heavy sweating or diarrhoea, or a strict low-salt diet

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

A previous bad reaction to lithium
Milder kidney or thyroid issues
Other medicines: especially anti-inflammatory painkillers (e.g. ibuprofen), water tablets (diuretics), and some blood-pressure medicines, which can push your lithium level up
Pregnant, planning to be, or breastfeeding (see the section below; this one matters more than for most medicines)

You'll have regular blood tests for your lithium level, and your thyroid and kidneys. Keep your fluid and salt intake steady from day to day, and let your doctor know if you become ill with vomiting, diarrhoea, or fever, as these can raise your lithium level.

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

Lithium is taken every day, usually in one or two doses, at a dose set by your blood level rather than a standard number.

If you miss a dose: skip it if the next one is close. Never double up; with lithium, an extra dose isn't harmless
Keep your habits steady: roughly consistent fluid and salt intake day to day matters more with lithium than with most medicines
Tell any other doctor treating you that you take lithium before new medicines are added

What side effects should I expect?

Most are mild, and several can be eased with a counter-medicine if they persist. Not everyone gets them.

A fine trembling of the hands
Dry mouth and thirst
Passing more urine than usual
Nausea, or loose stools
Over time, changes in thyroid function: which is why it's checked on your blood tests

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

Finally, the one thing to know with lithium: if the level climbs too high it can cause trouble (lithium toxicity). The regular blood tests exist precisely to keep this from happening, so it's uncommon; just get in touch straight away if you notice:

A coarse, shaky tremor (different from the usual fine trembling)
Ongoing vomiting or diarrhoea
Unsteadiness or slurred speech, or feeling unusually drowsy or confused

Will I become dependent? How do I stop safely?

No; lithium isn't habit-forming. But stopping suddenly is one of the riskier moves in psychiatry: mood symptoms, especially mania, can return hard. Any change is made gradually, with your doctor, usually over weeks to months, with the blood tests continuing along the way.

Can I drive while taking it?

The Japanese label advises against driving while taking it. Lithium can cause drowsiness or dizziness in some people, and the label here instructs that patients on it shouldn't drive or operate dangerous machinery. Once you're stable on a steady level and feel clear, discuss your own situation with your doctor.

What about pregnancy and breastfeeding?

This is the one conversation to have early, before pregnancy if possible. Lithium can affect the baby's developing heart, so in pregnancy it's avoided except when truly necessary, and breastfeeding on lithium is generally avoided (it passes into milk in meaningful amounts). At the same time, never stop lithium suddenly on discovering a pregnancy; sudden withdrawal risks a severe relapse, which is dangerous for both of you. The safe path is an early, planned conversation. Our guides to medication in pregnancy and medication while breastfeeding cover the wider picture.