Lithium

What it treats

Lithium is approved by the U.S. Food and Drug Administration for bipolar disorder. It is used to treat acute manic episodes, and it is used as long-term maintenance treatment to prevent future episodes of mania and depression.

It is also used off-label to boost the effect of an antidepressant in depression that has been hard to treat. Off-label means a use that the FDA label doesn't formally list, even though evidence and clinical practice support it.

One point sets lithium apart from many other psychiatric medications. It has good evidence for reducing the risk of suicide in people with mood disorders. That is part of why it remains a benchmark treatment decades after it was introduced.

How it works

Lithium is a naturally occurring element. It is taken as a simple salt, in tablet, capsule, or liquid form.

Despite decades of use, exactly how lithium stabilizes mood is still not fully understood. It is known to affect several signaling pathways inside nerve cells, the chemical steps a cell uses to pass along and respond to messages. Researchers think those effects gradually steady the brain systems involved in mood. The honest summary is that lithium clearly works for many people, and the precise mechanism is still being studied.

What to expect

Common side effects

Most people on lithium notice some side effects. The common ones include:

• Increased thirst and more frequent urination.
• A fine hand tremor, a small steady shake that is usually mild.
• Nausea, especially early on.
• Weight gain.
• Loose stools for some people.
• A mild sense of mental dullness or slowed thinking for some people.

Many of these are dose-related, which means they ease if the level can be lowered while staying effective. Taking lithium with food can help with nausea. If a side effect is bothersome or not improving, that's a conversation to have with the prescriber rather than a reason to stop on your own.

Serious side effects and warnings

The most important risk to understand with lithium is toxicity.

Boxed warning. Lithium has a narrow therapeutic range, which means the blood level that works and the level that becomes toxic are close together. Lithium toxicity is serious and can be life-threatening, and it can develop even at doses near the normal range. Warning signs include a worsening tremor, confusion, vomiting, diarrhea, drowsiness, and unsteadiness on your feet. These signs need urgent medical attention. This is why regular blood tests to check the lithium level are an essential part of treatment, not an optional extra.

• Things that can raise the lithium level. Dehydration, heavy sweating, and low-salt diets can all push the level up and raise the risk of toxicity. So can certain medications, including NSAID painkillers such as ibuprofen, some blood pressure medications, and diuretics, also called water pills.
• Effects on the kidneys and thyroid. Over the long term, lithium can affect how the kidneys work and can affect the thyroid gland. Because of this, kidney and thyroid function are checked periodically with blood tests.
• Mood switch. A switch in mood is possible, so any new change in mood is worth reporting to the prescriber.

The practical message is simple. Lithium requires a commitment to regular blood work. Skipping the monitoring is the main way lithium becomes dangerous.

Sexual side effects

Lithium is not a notable cause of sexual side effects. This is one area where it tends to be easier than several other psychiatric medications. If sexual changes do appear, they are worth mentioning to a prescriber, since other factors or other medications may be involved.

Weight, appetite, and sleep

Lithium can cause weight gain, and for some people this is a real consideration over the long term. It is worth discussing with a prescriber, who can help with monitoring and practical steps.

Lithium is not a major sleep medication. It does not have a strong sedating effect, and it is not used as a sleep aid.

Starting and dosing basics

This section is general background, not a dosing instruction for any individual. The right dose is a decision for a prescriber.

Lithium comes as tablets, capsules, extended-release tablets, and a liquid. The dose is not chosen by a fixed number alone. It is adjusted to reach a target level in the blood, and the prescriber uses blood tests to guide it. That is why dosing is gradual and individualized.

Staying consistently hydrated and consistent with dietary salt matters more with lithium than with most medications. Big changes in fluid or salt intake can shift the lithium level, so steady habits help keep treatment safe.

Missed doses and interactions

If you miss a dose, the general guidance is to take it when you remember, unless it is almost time for the next dose. In that case, skip the missed dose and carry on. Don't take two doses to make up for one.

Several interactions can raise the lithium level and the risk of toxicity. NSAID painkillers such as ibuprofen, some blood pressure medications including ACE inhibitors and ARBs, and thiazide diuretics can all push the level up. Dehydration, vomiting, diarrhea, heavy sweating, and low-salt diets also raise it.

Because of this, tell every prescriber and pharmacist that you take lithium, including over-the-counter purchases. A new painkiller or blood pressure medication can change your lithium level, so it should be coordinated with the prescriber who manages your lithium.

Stopping and tapering

Lithium should not be stopped abruptly. Stopping suddenly raises the risk of a mood episode, including a return of mania.

If a change is needed, it should be gradual and planned with a prescriber, stepping the dose down over time. Deciding to stop because you feel well is understandable, but feeling well on lithium often means the medication is doing its job. Any change is worth doing slowly and with guidance.

Pregnancy and breastfeeding

This is an area where individual circumstances matter and the decision belongs with a clinician. Lithium use in pregnancy has been linked to a small increased risk of certain heart defects in the baby. At the same time, untreated bipolar disorder carries its own real risks during pregnancy.

There is no single answer that fits everyone. 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 for their situation.

Cost and generic availability

Lithium is available as a generic and is inexpensive. It is one of the lower-cost psychiatric medications. The main ongoing cost is not the drug itself but the regular blood tests and monitoring, which are a necessary part of safe treatment.

Common questions

Why does lithium need blood tests? Because lithium has a narrow therapeutic range. The level that works and the level that becomes toxic are close together. Blood tests confirm the level is in the safe, effective zone and check that the kidneys and thyroid are doing well.

What is lithium toxicity, and what are the warning signs? Toxicity means the lithium level has climbed too high. Warning signs include a worsening tremor, confusion, vomiting, diarrhea, drowsiness, and unsteadiness. These need urgent medical attention.

Does lithium cause weight gain? It can. Weight gain is a known side effect for some people and is worth discussing with a prescriber.

Can I take ibuprofen with lithium? Be careful. Ibuprofen and other NSAID painkillers can raise the lithium level. Check with the prescriber or pharmacist before using them regularly.

What happens if I stop lithium suddenly? Stopping abruptly raises the risk of a mood episode. Any change should be gradual and planned with a prescriber.

Questions to ask your prescriber

• What are we hoping this treats, and how will we know it's working?
• How often will I need blood tests, and what do they check?
• Which side effects should I expect, and which ones should I call about?
• What painkillers and over-the-counter medications are safe for me to use?
• If we decide to change or 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. Lithium prescribing information.
• MedlinePlus, U.S. National Library of Medicine. Lithium.
• National Institute of Mental Health. Mental health medications.