Synopsis
Initiate lithium only with complete baseline and shared-care safeguards, interpret correctly timed plasma levels, prevent interaction and dehydration-related harm, and act on clinical toxicity without waiting for a numerical threshold.
- Required baseline includes weight or BMI, full blood count, urea and electrolytes including calcium, eGFR and thyroid function; add ECG for cardiovascular disease or risk and assess pregnancy where relevant.
- Do not initiate lithium without facilities for regular plasma levels, organ monitoring, safety information and an explicit specialist-primary-care shared-care arrangement.
- First plasma level is measured one week after starting and one week after every dose change, then weekly until stable using the locally specified post-dose sampling time.
- For a person prescribed lithium for the first time, NICE usually targets 0.6 to 0.8 mmol/L; consider 0.8 to 1.0 mmol/L for at least six months only in specified relapse or residual-symptom circumstances.
- Measure levels every three months during the first year, then every six months, or every three months in older people and others with interaction, organ, adherence, symptom or higher-level risk.
- Check weight or BMI, eGFR, urea and electrolytes, calcium and thyroid function every six months, increasing frequency when results change or symptoms suggest organ effects.
- Teach stable fluid and salt intake, action during vomiting, diarrhoea or acute illness, avoidance of over-the-counter NSAIDs and prompt reporting of pregnancy or toxicity symptoms.
- Toxicity is a clinical diagnosis supported by a level: withhold lithium and obtain urgent level and renal-electrolyte assessment whenever symptoms are concerning, even within the therapeutic range.
- If lithium is stopped, reduce over at least four weeks and preferably up to three months, with close relapse monitoring during reduction and for three months afterward.
Key red flags
Coarse tremor, unsteady gait, dysarthria, confusion, reduced consciousness, seizure or new neuromuscular signs suggests clinically significant neurotoxicity.
Vomiting, diarrhoea, fever, profuse sweating, poor fluid intake or acute kidney injury can rapidly raise lithium exposure and requires sick-day assessment.
A newly prescribed NSAID, ACE inhibitor, angiotensin receptor blocker or diuretic can increase lithium concentration and needs immediate interaction review and extra monitoring.
Syncope, bradycardia, arrhythmia, severe hypotension or collapse during lithium treatment requires urgent ECG, electrolyte and medical evaluation.
Pregnancy, planned pregnancy or significant decline in eGFR changes the benefit-harm balance and requires coordinated specialist review rather than abrupt stopping.
Investigation priorities
Measure weight or BMI, FBC, renal function, electrolytes, calcium and thyroid function before exposure.
Management branches
Lithium is selected for an adult who has not previously taken it or is restarting after a clinically significant interruption.
- Discuss benefits, adverse effects, toxicity, interactions, pregnancy, adherence and discontinuation and confirm the person can use monitoring and safety information.
- Complete weight or BMI, FBC, renal-electrolyte-calcium and thyroid tests, plus indicated ECG and pregnancy assessment, before prescribing.
- Start the product-specific regimen under specialist oversight, document shared-care responsibilities and schedule the first correctly timed level at one week.
The lithium dose and plasma concentration are stable without current toxicity or relapse concern.
- Check the plasma level every three months during year one and thereafter at the six- or three-month interval determined by individual risk.
- Measure renal function, electrolytes, calcium, thyroid function and weight or BMI at least every six months and act on trends.
- At every contact review symptoms, sick-day events, hydration, salt change, pregnancy intentions, adherence and newly prescribed or over-the-counter interactions.