Lithium (Lithium salts) – Patient Guide (UK)

Lithium is a medicine used mainly to treat mood disorders, particularly to prevent mood episodes in certain people with bipolar disorder. It has a long history of use, but it requires careful monitoring because the amount needed to be helpful is close to the amount that can cause side effects. This guide explains how lithium works, how it behaves in the body, how to take it safely, common interactions, and what to expect while using it in the United Kingdom.

Basic product information

Medicine name: Lithium (commonly lithium carbonate or lithium citrate, depending on brand/formulation).
ATC code: N05AN01 (Lithium).
Common form: Tablets or capsules (formulation varies by brand).
How it’s supplied: Available via UK pharmacies; availability depends on local supply and the specific product.

Important: Lithium dosing is individual. Your prescriber will adjust your dose based on blood test results, response, kidney and thyroid health, age, and any interacting medicines.

How lithium works (mechanism of action)

Lithium affects several pathways in the brain and body. While the exact mechanism is complex and not fully understood, lithium is known to influence:

• Neurotransmitter signalling involved in mood regulation.
• Second messenger pathways (e.g., enzymes involved in cell signalling).
• Glycogen synthase kinase-3 (GSK-3) related signalling which may contribute to mood stabilisation.
• Cellular resilience through effects on neuronal activity and plasticity.

In practice, lithium is most valued for its mood-stabilising and anti-relapse effects, helping reduce the risk of future manic and depressive episodes in people with bipolar disorder.

What lithium is used for (indications)

In the UK, lithium is mainly used for:

• Maintenance treatment of bipolar disorder (helping prevent recurrence of mood episodes).
• Reducing risk of relapse in eligible people with bipolar illness, especially where past responses support its use.
• Some cases of acute mania may involve lithium as part of a broader treatment plan, depending on clinical assessment.

Your healthcare team will determine whether lithium is appropriate for you based on your diagnosis, history, overall health, and ability to attend monitoring.

Timing and how to take lithium

Lithium is usually taken once daily or in divided doses, depending on the formulation and your prescribed plan. It’s important to take it at the same times each day and to follow the exact instructions given to you.

When to take your dose

• Evening vs morning: Some regimens are once daily at night; others may be split. Follow your prescription instructions.
• Consistency matters: Try not to vary the time of doses from day to day.
• Blood tests: Lithium levels are usually taken as a trough level (just before your next dose) to guide dosing.

Missed dose

If you miss a dose, take it as soon as you remember unless it is close to the time of the next dose. Do not take a double dose. If you are unsure, contact your pharmacy or prescriber for advice.

Dose information (general guidance)

Lithium is dosed according to blood levels and individual response. The goal is typically a level within the therapeutic range for the intended treatment while minimising side effects.

Because dosing varies widely, the safest approach is:

• Use the dose and schedule your clinician provides.
• Have lithium blood tests at the recommended times, especially during the first weeks and after dose changes.
• Do not start, stop, or change the dose without clinical advice.

Monitoring plan (why it matters)

Monitoring helps protect kidneys and the brain, and ensures the medicine stays in the effective range. Your clinician will advise on:

• Lithium blood concentration (levels should be checked regularly).
• Kidney function (e.g., creatinine/eGFR).
• Thyroid function.
• Electrolytes as needed.
• Medication and fluid status review (including interactions).

Pharmacokinetics (how lithium moves through the body)

Understanding pharmacokinetics helps explain why monitoring is crucial. Lithium is absorbed and distributed through body fluids, and it is eliminated mainly by the kidneys.

Absorption

• Lithium is absorbed from the gastrointestinal tract.
• Absorption may vary between formulations and individuals.

Distribution

• It distributes into body water and can reach the brain.
• Because it follows water balance, changes in hydration can influence lithium levels.

Metabolism

• Lithium is not meaningfully metabolised by the liver.
• It remains as lithium in the body.

Elimination

• Elimination is largely renal (through the kidneys).
• Kidney function, hydration, and sodium balance strongly affect lithium clearance.

Half-life and practical meaning

Lithium has a relatively long half-life. This means changes in dose or interacting factors can take time to reflect in blood levels, and the effects may build up if clearance is reduced.

Food interactions

Lithium itself is generally taken with or without food depending on the product and your routine. Food interactions are less common than interactions involving dehydration or sodium balance, but practical factors still matter.

• Consistent salt and hydration: Sudden changes in salt intake can affect lithium levels.
• Hydration matters more than meals: Vomiting, diarrhoea, or not drinking enough fluid can increase lithium levels.
• Dieting or severe low-salt diets: These may affect lithium handling; discuss dietary changes with your clinician.

If you are following a special diet, have appetite changes, or are planning lifestyle changes, let your healthcare team know.

Alcohol and medicine interactions

Alcohol can worsen side effects such as dizziness, drowsiness, and dehydration risk. Lithium requires stable hydration and kidney function, so drinking alcohol in excess can make lithium harder to manage safely.

Alcohol (practical advice)

• Moderation is key: Avoid heavy or binge drinking.
• Watch for dehydration: Alcohol may contribute to reduced fluid intake.
• Be aware of mood and sleep impacts: Alcohol can destabilise sleep and mood in some people.

Medicines that may interact with lithium

Interactions can occur through reduced kidney clearance or changes in sodium balance. Always check with a pharmacist before starting, stopping, or changing any medicine, including over-the-counter products.

Common interaction groups to be aware of include:

• Non-steroidal anti-inflammatory drugs (NSAIDs) (e.g., ibuprofen, naproxen, diclofenac) can raise lithium levels.
• Diuretics (especially thiazides) may increase lithium levels.
• ACE inhibitors and ARBs (for blood pressure/heart conditions) may increase lithium levels.
• Some antibiotics and other medicines may affect lithium concentrations indirectly—check with your pharmacist.
• Serotonergic medicines and other psychiatric medicines: interactions vary; your clinician will consider your overall regimen.
• Dehydrating agents or situations (e.g., significant vomiting/diarrhoea) can raise lithium levels.

Herbal products: Some supplements and herbal remedies can affect hydration, kidney function, or drug handling. Ask a pharmacist before using them.

Safety profile: side effects and red flags

Lithium can cause side effects, particularly if blood levels are too high. Many side effects can be managed with dose adjustment and monitoring, but severe toxicity requires urgent medical attention.

Common side effects

• Tremor (shakiness), often dose-related.
• Increased thirst and increased urination.
• Gastrointestinal upset (e.g., nausea or diarrhoea).
• Weight gain in some people.
• Fatigue or feeling slowed down.
• Some changes in thyroid function (thyroid monitoring is important).

Serious side effects / signs of possible toxicity

If you develop symptoms suggesting lithium levels may be too high, seek urgent advice. Call NHS 111 or your healthcare team, or call emergency services if severe.

• Severe worsening tremor or unsteadiness
• Confusion, extreme drowsiness, or reduced alertness
• Slurred speech
• Persistent vomiting or severe diarrhoea
• Severe dizziness or fainting
• New significant weakness or seizures (rare but urgent)

Early toxicity can be subtle. If you are unwell (for example with vomiting or diarrhoea) or you think hydration has dropped, contact your healthcare team promptly. They may advise temporarily holding or adjusting the dose based on your situation.

Practical use tips for safe day-to-day management

Stay consistent with fluids

• Try to drink steadily through the day.
• Seek advice if you can’t keep fluids down (e.g., vomiting/diarrhoea).
• Be cautious during hot weather or heavy exercise.

Be careful with salt and dehydration

• A sudden low-salt intake may affect lithium levels.
• Don’t deliberately change your salt intake without advice.
• Inform your clinician if you have conditions that affect fluid balance.

Keep medication information up to date

• Carry a list of your medicines and doses.
• Inform any healthcare professional you see that you take lithium.
• Check new OTC medicines (especially pain relief and cold/flu products) with a pharmacist.

Attend blood test appointments

Blood tests are a key part of safe lithium therapy. Missing tests can make it difficult to keep lithium within the target range.

Plan around illness

• If you develop significant vomiting or diarrhoea, contact your healthcare team quickly.
• Do not assume it is safe to “carry on as usual” while dehydrated.

Driving and machinery

Lithium can cause tiredness, dizziness, or tremor in some people. If you feel affected, avoid driving or operating machinery until you’re sure you can do so safely.

Kidney and thyroid considerations

Because lithium is cleared by the kidneys, kidney function is central to safe use. Lithium can also influence thyroid function.

• Kidneys: Your clinician will monitor kidney function regularly and adjust dosing if needed.
• Thyroid: Thyroid tests may be checked and treated if hypothyroidism occurs.

If you have existing kidney disease, discuss suitability and monitoring frequency with your healthcare team.

Alternative options

Depending on your diagnosis, symptoms, and past response, clinicians may consider alternatives to lithium such as:

• Other mood stabilisers (e.g., certain anticonvulsants used in bipolar disorder).
• Antipsychotic medicines for acute episodes or prevention in selected cases.
• Psychological interventions (e.g., structured therapies) alongside medication in appropriate circumstances.

The choice of alternative depends on medical history, side effect profile, interactions, pregnancy considerations, and the need for monitoring. Your clinician can help determine the most suitable option for you.

Pharmacovigilance and UK market/legal context

Lithium is an established medicine within the UK. It is regulated by UK pharmaceutical legislation and monitored through the UK’s pharmacovigilance systems. Healthcare professionals and patients are encouraged to report suspected adverse reactions.

Regulatory and safety messages: Because lithium has a narrow range between effective and potentially toxic levels, UK guidance emphasises monitoring and review. Advice may change over time as new evidence becomes available.

Recent guidance (how to stay informed)

Guidance for mood disorders and medicines safety is regularly updated in the UK. Clinicians may follow:

• National treatment guidance for bipolar disorder and maintenance therapy.
• Local formulary and shared-care protocols for monitoring lithium.
• Safety communications regarding interactions and monitoring schedules.

If you’d like, consult your prescriber or pharmacist for the most up-to-date local monitoring plan.

Delivery, availability, and ordering in the UK

Availability of lithium depends on the specific product (brand/formulation) and local supply. Online pharmacies in the UK may offer:

• Standard delivery: Typically several working days (varies by provider).
• Express options: Sometimes available for urgent supplies.
• Stock updates: Some medicines may be temporarily unavailable; substitutions are usually only offered where permitted.

If a product is out of stock, a pharmacist can often discuss alternatives that are clinically appropriate. Always ensure you receive the exact formulation you’ve been monitored on, because different preparations may have different dosing schedules.

When to seek urgent help

Contact urgent medical help if you develop symptoms suggestive of toxicity (especially severe confusion, persistent vomiting, unsteadiness, or seizures) or if you are suddenly unable to maintain fluid intake.

• Call NHS 111 for urgent advice when it’s not life-threatening.
• Call emergency services if symptoms are severe or rapidly worsening.

Summary of key safety points

• Lithium can be very effective for preventing mood relapses in bipolar disorder, but it requires monitoring.
• Levels depend strongly on kidney function, hydration, and interactions (especially with NSAIDs, diuretics, and some blood pressure medicines).
• Stay consistent with fluids and do not make major salt or hydration changes without advice.
• Attend regular blood tests and thyroid/kidney monitoring.
• Know toxicity warning signs and seek help early if you’re unwell.

Product overview at a glance

FAQ

How quickly does lithium work?

Response varies. Some benefits may be noticed within days to weeks, but lithium is often valued for long-term relapse prevention. Your clinician will monitor progress and blood levels to guide ongoing dosing.

Why do I need regular blood tests?

Lithium levels need to stay within a therapeutic range. Too low may not help; too high increases the risk of toxicity. Testing also helps detect kidney or thyroid changes early.

Can I take lithium with food?

Many people take lithium with or without food depending on comfort and the specific formulation. The most important practical factors are consistent hydration and avoiding dehydration. Follow your personal instructions from your healthcare team.

What should I do if I become ill with vomiting or diarrhoea?

Seek advice promptly from your healthcare team (or NHS 111 if you can’t reach them). Vomiting and diarrhoea can cause dehydration, which may increase lithium levels and the risk of side effects.

Is it safe to drink alcohol while taking lithium?

Alcohol may increase side effects and dehydration risk. It’s best to avoid heavy drinking and to maintain good hydration. If you are unsure, ask your pharmacist or prescriber about what is suitable for you.

What pain relief can I use?

Some painkillers (especially NSAIDs like ibuprofen and naproxen) can raise lithium levels. Speak to a pharmacist for advice on which options are safest for you.

Can I stop lithium suddenly?

Do not stop lithium suddenly without medical advice. Stopping can increase the risk of relapse. If you have concerns, speak with your clinician so they can plan a safe adjustment strategy.

Does lithium affect driving?

It can, particularly if you feel tired, dizzy, or unsteady. If you notice these effects, avoid driving or operating machinery until you’re sure it’s safe.

Are there alternatives if I can’t tolerate lithium?

Yes. Depending on your situation, clinicians may consider other mood stabilisers or different treatment combinations. Discuss side effects and concerns early so the best option can be chosen.

Where can I report side effects?

In the UK, suspected side effects can be reported via the MHRA Yellow Card scheme. Your pharmacist or healthcare professional can also help.

Disclaimer: This guide is for general information and does not replace advice from a healthcare professional. If you have specific questions about your situation, medicines, or monitoring schedule, contact your pharmacist or clinician.