Lithium (Lithium salts) – Patient Information for the United Kingdom

Lithium is a medicine used mainly to treat and help prevent certain mood disorders, particularly bipolar disorder. Because lithium can affect the kidneys and thyroid and must be carefully monitored, it is important to take it exactly as directed and to attend regular blood tests. This page explains how lithium works, how it behaves in the body, how to take it safely, and what to expect in everyday life in the UK.

1) Basic product information

• Medicines commonly available: lithium carbonate (many brands), and other lithium salt formulations depending on local availability.
• Common strengths: vary by brand and formulation.
• How it is taken: usually by mouth, either as immediate-release or modified/controlled-release preparations.
• When it starts working: mood stabilisation is not usually immediate; improvements often take days to weeks, while prevention of relapse may take longer.
• Key safety feature: regular monitoring of lithium level (blood “lithium” or “serum lithium”), kidney function, and thyroid function.

Note: Different formulations (immediate vs modified/controlled release) are not always interchangeable. Always follow the specific instructions for your product.

2) What lithium does (mechanism of action)

Lithium is a mood stabiliser. Its exact mechanism is complex and not fully understood, but it is thought to:

• Stabilise brain signalling: lithium influences neurotransmitter systems (including pathways involved in mood regulation).
• Reduce “overactivity” in mood circuits: it may help balance signals that contribute to mania/hypomania and reduce relapse risk.
• Affect intracellular processes: lithium can alter cellular signalling pathways and second messenger systems, which may contribute to longer-term symptom control.

In short, lithium helps reduce the likelihood of mood swings in susceptible people, particularly over the long term.

3) Pharmacokinetics (how the body handles lithium)

Lithium has narrow therapeutic range, meaning the difference between effective and potentially harmful levels can be small. Understanding how it is handled helps explain why monitoring is essential.

Why this matters: small changes in kidney function, hydration, or salt balance can alter lithium levels. Some medicines and illness (e.g., vomiting or diarrhoea) can increase risk of toxicity.

4) Typical uses in the UK

In the UK, lithium is commonly used for mood stabilisation in:

• Bipolar disorder (to help treat certain mood episodes and to help prevent relapse).
• Recurrent mood symptoms where long-term stabilisation is needed, particularly when other options have not been fully effective.

Clinicians may also consider lithium in other specialist contexts depending on individual circumstances. The safest approach is to use lithium only as advised by your healthcare team.

5) Indications (when lithium is used)

Your exact indication may depend on your history and formulation. Typical indications include:

• Maintenance therapy for bipolar disorder to reduce the frequency and severity of relapse.
• Acute management in selected situations, often alongside other approaches (especially in severe or recurrent cases).

Important: Lithium is not the right medicine for every mood disorder. A careful assessment is required to ensure it matches your diagnosis and risk profile.

6) How to take lithium (timing and dosing)

Lithium must be taken consistently. Your dose is usually based on blood test results, kidney function, symptom control, and the specific product (immediate vs modified/controlled release).

6.1 Typical dosing approach

Because of the monitoring requirements and narrow therapeutic range, dose instructions should always come from your clinician. In general, clinicians aim to keep your lithium level in a safe, effective range for you.

• Start low and adjust slowly: doses are commonly increased gradually to reach a target lithium level.
• Monitoring guides dose changes: blood levels are checked and dosing adjusted accordingly.
• Special populations: older adults, people with reduced kidney function, and those with increased risk of dehydration may require lower doses and closer monitoring.

6.2 Timing with blood tests

To interpret lithium levels correctly, blood tests are usually taken at a consistent time relative to your last dose. This timing depends on your formulation:

• Immediate-release: levels are often checked as a trough (just before the next dose), or as otherwise specified by your clinic.
• Modified/controlled release: the timing may differ. Your clinic will give exact instructions.

Practical tip: set reminders for both your dose and your scheduled blood test. Keep a note of when you took your last tablet before the test.

6.3 Taking lithium with or without food

Lithium can often be taken with or without food. If food helps you remember or reduces stomach upset, taking it with meals may be practical. However, the most important factor is consistency and adhering to the same routine each day.

7) Food interactions and hydration

Unlike many medicines, lithium levels are strongly influenced by body water and sodium balance.

7.1 Fluid intake and dehydration

• Maintain consistent hydration: dehydration can increase lithium levels and toxicity risk.
• Hot weather and exercise: be careful with sweating and ensure adequate fluids.
• Illness with vomiting/diarrhoea: dehydration can develop quickly. Seek urgent advice if you become acutely unwell.

7.2 Salt (sodium) intake

Large changes in salt intake can affect lithium concentration:

• Sudden low-salt diets may increase lithium levels.
• Sudden high-salt intake may lower lithium levels.

If you plan dietary changes, discuss them with your clinician/pharmacist.

7.3 Caffeine and drinks

Normal caffeine intake is generally tolerated for many people, but individual responses vary. Avoid large, sudden changes in fluid intake or caffeine habits.

8) Alcohol interactions

Alcohol may not directly raise lithium levels in the same way as dehydration does, but it can increase risks indirectly by:

• Contributing to dehydration (especially with binge drinking)
• Worsening mood symptoms or sleep quality
• Increasing risk of drowsiness and impaired coordination when combined with other medicines (e.g., sedatives)

Patient-friendly guidance: If you drink alcohol, keep it moderate and consistent. Avoid binge drinking and seek advice if you have concerns about drinking or if you become unwell after alcohol.

9) Interactions with other medicines (including common UK examples)

Lithium interacts with a range of medications, often because they affect kidney function, sodium balance, or fluid status. Some interactions can lead to dangerously high lithium levels.

Always tell your healthcare team and pharmacist about all medicines you take, including:

• over-the-counter medicines
• herbal products
• supplements
• painkillers and anti-inflammatory drugs

9.1 Pain relief and anti-inflammatory medicines

Non-steroidal anti-inflammatory drugs (NSAIDs) can increase lithium levels in some people. Examples include:

• ibuprofen
• diclofenac
• naproxen

Paracetamol (acetaminophen) is often preferred for mild pain/fever, but you should still confirm what is safe for you.

9.2 “Water tablets” (diuretics)

Some diuretics can significantly affect lithium levels. Examples include:

• thiazide-type diuretics
• loop diuretics

If a diuretic is needed, careful monitoring is essential.

9.3 Blood pressure and heart medicines

Some treatments for blood pressure and heart conditions can affect lithium concentrations, particularly:

• ACE inhibitors
• angiotensin receptor blockers (ARBs)

9.4 Other mood medicines and sedatives

Some other psychotropic medicines may increase side effects such as drowsiness or affect hydration/safety indirectly. Your clinician will consider the full regimen.

9.5 “Sick day” medicines and dehydration risk

Any situation that increases dehydration (e.g., diarrhoea/vomiting, fever with poor intake) can increase toxicity risk. Medication changes during acute illness should be discussed with your clinician.

10) Safety profile: side effects, serious risks, and monitoring

Lithium can be very effective, but it requires careful safety management. Monitoring helps detect changes early.

10.1 Common side effects

Some side effects may improve after dose adjustment or over time. Commonly reported effects include:

• increased thirst and frequent urination
• mild nausea or stomach discomfort
• hand tremor
• weight gain in some people
• tiredness
• mild changes in concentration or coordination

10.2 Signs of lithium toxicity (urgent)

Lithium toxicity can occur if levels become too high, particularly due to dehydration, kidney impairment, or drug interactions. Seek urgent medical advice if you notice symptoms such as:

• severe or worsening tremor
• unsteadiness, dizziness, or difficulty walking
• confusion, unusual drowsiness, or agitation
• slurred speech
• persistent vomiting or severe diarrhoea
• blurred vision

Emergency warning: If symptoms are severe or rapidly worsening, seek emergency care immediately.

10.3 Kidney and thyroid effects

• Kidneys: lithium is cleared through the kidneys. Long-term use can affect kidney function in some people.
• Thyroid: lithium can affect thyroid hormone levels, sometimes leading to hypothyroidism.

10.4 Monitoring schedule (typical)

Exact schedules vary, but monitoring often includes:

• Lithium blood level: checked frequently when starting or changing dose, then less often once stable.
• Kidney function: urea/creatinine and estimated glomerular filtration rate (eGFR).
• Thyroid function: thyroid-stimulating hormone (TSH) and related tests.
• Clinical review: assessment of side effects and mood stability.

Your clinic may provide a specific monitoring plan tailored to you.

11) Practical use tips (how to take lithium safely in daily life)

• Take it at the same time each day and follow the dosing instructions exactly.
• Attend blood tests promptly, and ensure timing matches your clinic instructions.
• Stay hydrated, especially in hot weather, during exercise, or if you’re unwell.
• Be cautious during “sick days”: if you have vomiting/diarrhoea, high fever, or you’re not drinking normally, contact your healthcare team urgently for advice.
• Avoid sudden diet changes, especially drastic changes in salt intake.
• Check before taking new medicines: ask your pharmacist about over-the-counter painkillers and cold/flu remedies.
• Keep a medicines list (including dose and formulation) for quick reference.
• Report new symptoms early, particularly tremor changes, unsteadiness, or confusion.

12) Alternative options

The choice of treatment depends on your diagnosis, previous response, side effects, and overall health. Options that clinicians may consider include:

• Other mood stabilisers (for example, certain anticonvulsant medicines used for bipolar disorder)
• Antipsychotic medicines for acute mania/hypomania and some maintenance strategies
• Psychological support alongside medication to help manage routines, early warning signs, and relapse prevention

Never stop or adjust lithium without medical guidance. If you’re concerned about side effects or levels, discuss it with your healthcare team—dose adjustment or additional monitoring may be possible.

13) UK market and legal/regulatory context (patient-friendly overview)

In the UK, lithium medicines are supplied under medicines regulations and clinical governance. Lithium requires:

• careful prescribing and risk assessment by healthcare professionals
• structured monitoring for lithium levels and organ function
• pharmacist involvement to reduce interaction risks and support safe use

As guidance evolves, UK clinical practice may be updated by professional bodies and national medicines safety communications. Always follow the instructions provided by your local clinic and medicines team.

14) Recent guidance and monitoring awareness (general updates)

Across recent years, UK and international safety messages have consistently emphasised:

• prompt monitoring after starting or changing dose
• extra caution during intercurrent illness (dehydration risk)
• attention to drug–drug interactions, particularly NSAIDs and diuretics
• clear patient education about toxicity symptoms and when to seek help

If you have not reviewed your “what to do when unwell” plan recently, ask your healthcare team for an updated plan tailored to you.

15) Delivery and availability (UK online pharmacy)

Availability of lithium products can vary by brand and formulation. When ordering online in the UK, you can typically expect:

• Clear product details (salt form, formulation type, and strength)
• Delivery options depending on your postcode and stock status
• Packaging designed for safe transport
• Dispatch timelines that depend on whether the item is in stock

Important: If you’re switching between brands or formulation types, confirm this with your prescriber and check whether your blood test timing needs to change.

16) FAQ

How quickly does lithium start working?

For mood stabilisation, effects are not usually instant. Some people notice improvements within days, but fuller stabilisation may take weeks. Ongoing monitoring helps confirm the dose is appropriate.

Why do I need blood tests if I feel okay?

Lithium levels can change without obvious symptoms, especially with dehydration, kidney changes, or interacting medicines. Blood tests help prevent toxicity and ensure you remain within your safe target range.

Can I take lithium with food?

Often yes. What matters most is taking it consistently and following your specific instructions for your formulation.

What should I do if I have vomiting or diarrhoea?

Contact your healthcare team urgently for advice. Dehydration can raise lithium levels quickly. Follow your “sick day” plan—do not wait for symptoms to become severe.

Can I take ibuprofen or other anti-inflammatory painkillers?

NSAIDs such as ibuprofen can increase lithium levels in some people. It’s safer to ask your pharmacist or clinician what pain relief is appropriate for you.

Do I need to avoid salt?

Don’t make sudden drastic changes. Your body’s sodium balance influences lithium. Keep your salt intake consistent unless your clinician advises otherwise.

Is it safe to drink alcohol while taking lithium?

Moderation and consistency are key. Avoid binge drinking and be mindful of dehydration and sleep/mood effects. Seek advice if alcohol use is frequent or problematic.

What are the early signs that my lithium level might be too high?

Early warning signs can include increasing tremor, unsteadiness, dizziness, nausea/vomiting, or unusual tiredness/confusion. If you suspect toxicity, seek urgent medical advice.

Can I switch between immediate-release and modified/controlled-release lithium?

Usually switches require careful adjustment and monitoring. Formulations are not always interchangeable, so confirm changes with your healthcare team.

Who should be extra cautious with lithium?

People with kidney disease, older adults, those prone to dehydration, and those taking interacting medicines (such as NSAIDs or certain diuretics) often need closer monitoring.

What happens if I miss a dose?

Follow the advice given by your healthcare team or medicine leaflet for missed doses. In general, don’t double up. If you’re unsure, contact your pharmacist for guidance.

Always read the patient information leaflet provided with your specific lithium product and follow your healthcare team’s instructions. If you have questions about interactions, monitoring, or side effects, speak to your pharmacist or prescriber.