Lithium for bipolar disorder: what to expect

Lithium is a mood stabilizer — one of the longest-established and most-studied treatments in bipolar disorder. It can help reduce both the highs and the lows, and it is one of the few treatments with evidence for lowering suicide risk over time when used for long-term maintenance. None of that means it’s right for everyone; whether to take it is a decision for you and your prescriber. This page is educational, not medical advice — a plain-language guide to what living with lithium tends to involve, so your conversations with your care team are better informed.

Why the monitoring matters

Lithium’s great strength and its main demand come from the same fact: it works within a narrow range. Too little and it doesn’t help; too much and it becomes unsafe. That’s why prescribers check blood levels periodically — more often when starting or changing dose — and keep an eye on kidney and thyroid function over the longer term, since lithium can affect both. This routine isn’t red tape; it’s precisely what makes years of safe use possible. Keeping lab appointments is as much a part of the treatment as the tablet itself.

Hydration and the narrow range

Because lithium levels track with your body’s fluid and salt balance, everyday things can nudge them. Anything that dehydrates you — a stomach bug with vomiting or diarrhea, heavy heat or exercise, a crash diet, or heavy drinking — can push levels up. So can a change in how much salt you eat: a low-salt diet raises lithium levels — worth flagging if anyone ever advises you to cut salt for your blood pressure — and a big jump in salt can push them the other way. And so can some common medicines: over-the-counter anti-inflammatory painkillers (such as ibuprofen or naproxen) and certain blood-pressure medicines, especially diuretics (water tablets). The practical habit is simple: keep your fluids steady, and check with your prescriber or pharmacist before adding any new medicine, including ones you can buy without a prescription. Ask specifically what to do on “sick days,” when illness can change your levels fast.

Know the warning signs

Because the margin is narrow, it’s worth knowing what levels getting too high can look like, so you can act early. Contact your prescriber or seek urgent care if you notice new or worsening nausea or vomiting, diarrhea, a coarse hand tremor, unusual drowsiness or confusion, slurred speech, or unsteadiness on your feet. These can be signs of lithium toxicity, which is a medical issue to address promptly rather than wait out. Knowing the list isn’t meant to alarm you — it’s the same reason you learn the warning lights on a car.

Pregnancy, if it applies to you

Lithium and pregnancy is a balance rather than a simple no — and it is a conversation to have before conception, not after a positive test.

Lithium taken early in pregnancy carries a small increase in the risk of a particular heart defect. That risk is real, and it is also smaller than its reputation. Set against it: stopping lithium is not the safe default. Relapse after stopping is common, and the weeks after giving birth are the highest-risk period in the whole of bipolar disorder. This is a different situation from valproate, where the warning in pregnancy is much starker.

Levels move, too. The kidneys clear lithium faster as pregnancy goes on, so the amount in your blood tends to drop; around delivery it can climb again quickly. That means more frequent monitoring and a plan for the birth itself. Breastfeeding needs its own conversation.

If pregnancy is possible for you, raise it early — even if it isn’t the plan for this year. Many pregnancies are unplanned, and the useful version of this conversation is the one that happens in advance. See bipolar and pregnancy for the wider picture.

Questions for your prescriber

Bring these to an appointment: How often will we check my levels, kidney, and thyroid? What should I do if I’m ill or can’t keep fluids down? Which painkillers or other medicines should I avoid? What are the exact signs of levels being too high, and who do I call? Put the answers on your Medication Map so they’re there when you need them.

The rule that doesn’t change

Never start, stop, or change your dose on your own — that’s a decision for you and your prescriber. If you ever think your level may be too high, treat it as urgent rather than adjusting anything yourself.

Common questions

Does lithium need blood tests?

Yes. Lithium works within a narrow range, so prescribers check blood levels periodically — especially at the start or after a dose change — along with kidney and thyroid function over time. Your care team sets the schedule, and keeping those appointments is part of taking it safely.

Is lithium dangerous?

Used as prescribed and monitored, many people take it safely for years. Because the safe range is narrow, monitoring and steady hydration matter. Early signs of levels getting too high can include new or worsening nausea or vomiting, diarrhea, a coarse hand tremor, unusual drowsiness or confusion, slurred speech, or unsteadiness — reasons to contact your prescriber or seek urgent care.

Can I take lithium if I might become pregnant?

This is a balance rather than an automatic no, and it is a conversation to have before conception rather than after a positive test. Lithium taken early in pregnancy carries a small increase in the risk of a particular heart defect. Set against that, stopping is not the safe default: relapse after stopping is common, and the weeks after giving birth are the highest-risk period in bipolar disorder. Levels also shift during pregnancy and around delivery, so monitoring changes. Your prescriber weighs all of that with you — never stop on your own.

What everyday things can affect my lithium level?

Anything that shifts your fluid or salt balance: illness with vomiting or diarrhea, heavy heat or exercise, and big changes in how much you drink. Some common medicines — over-the-counter anti-inflammatories like ibuprofen or naproxen, and certain blood-pressure medicines — can also raise levels. Check with your prescriber or pharmacist before adding anything new.

Read next

• Bipolar Meds: Build a Toolkit (Not a Magic Pill)
• Bipolar medication: a calm, plain-language guide
• Can you drink alcohol on lithium?
• Mood stabilizer
• Bipolar and pregnancy: planning ahead

Sources

• NIMH — Mental Health Medications (mood stabilizers)
• MedlinePlus — Lithium
• DBSA — Medications

If you’re in crisis or thinking about harming yourself, you’re not alone and help is available right now. In the US & Canada call or text 988. In the UK & Ireland call 116 123 (Samaritans). Elsewhere, contact your local emergency services — Get Help Now lists lines by country.