Mood stabiliser
Lithium
Long-standing mood stabiliser with a narrow therapeutic index. Levels are taken 12 hours post-dose; thyroid, renal, calcium and weight are monitored regularly.
Indications
- Treatment and prophylaxis of bipolar disorder (mania and recurrent depression)
- Prophylaxis of recurrent unipolar depression
- Augmentation in treatment-resistant depression
- Aggressive or self-mutilating behaviour (specialist use)
Dosing
Initiation
Brand-prescribe — bioavailability differs between preparations. Typical Priadel start 400 mg at night (200 mg in older adults); titrate to target plasma level.
Therapeutic level
0.4–1.0 mmol/L (12 hours post-dose). Maintenance often 0.6–0.8 mmol/L; up to 1.0 mmol/L for acute mania or relapse prevention. >1.5 mmol/L is toxic.
Always confirm doses against the current BNF — this summary is for study, not prescribing.
Monitoring
- Lithium level 12 hours post-dose: weekly after initiation/dose change until stable, then every 3 months for the first year, then every 6 months
- U&E (eGFR, sodium), TFTs and calcium every 6 months — annually thereafter
- Weight at baseline and during treatment
- Pregnancy testing in women of childbearing potential before initiation
Contraindications
- Untreated hypothyroidism
- Significant renal impairment
- Cardiac disease — caution with arrhythmias; avoid in severe heart disease
- Addison's disease, dehydration, low-sodium diet
- Pregnancy first trimester — Ebstein anomaly risk (specialist decision)
Important interactions
- Thiazide and loop diuretics — reduce lithium clearance, increase levels
- ACE inhibitors and ARBs — increase lithium levels
- NSAIDs — increase lithium levels (avoid where possible)
- SSRIs — additive serotonergic effect; risk of neurotoxicity
- Haloperidol and other antipsychotics — risk of neuroleptic malignant syndrome
Counselling points
- Take consistently — do not double-up if you miss a dose
- Drink fluids regularly; avoid dehydration, especially in hot weather, vomiting, diarrhoea
- Maintain a stable salt intake — sudden low-sodium diets raise levels
- Report tremor, drowsiness, vomiting, or diarrhoea immediately
- Carry a lithium alert / patient information booklet
- Avoid OTC NSAIDs (ibuprofen) without checking with the pharmacist
- Use reliable contraception; planning pregnancy needs specialist input
Red flags
- Toxicity (level > 1.5 mmol/L) — coarse tremor, ataxia, drowsiness, vomiting, diarrhoea, confusion, seizures. Stop lithium and refer urgently for fluids ± haemodialysis at very high levels
- Acute kidney injury or dehydration — withhold and recheck level
- Pregnancy — specialist mental-health review urgently
Practice for the CRA
Drug-specific questions, calculations, and full mock exams aligned to the GPhC Common Registration Assessment.