Lithium

Side Effects

Short-Term

• CNS: Sedation, confusion, unsteadiness, tremors, dysarthria, seizures (in toxicity)

• Neuromuscular: Rigidity, hyperreflexia

• GI: Nausea, vomiting, diarrhoea

• Cardiovascular: QTc prolongation, possible hypovolaemia (especially from nephrogenic diabetes insipidus)

• Dermatological: Psoriasis flares or exacerbation

Long-Term

• Chronic lithium toxicity

• Nephrogenic Diabetes Insipidus (NDI)

• Hypothyroidism

• Hyperparathyroidism (hypercalcaemia)

• Weight Gain

Toxicity

Toxic Doses/Levels

• Acute: Ingestion >5 g or serum level >5 mmol/L

• Chronic: Serum level >1.5 mmol/L raises toxicity risk

Risk Factors

• Dehydration (reduces lithium clearance)

• Medications that decrease renal clearance: ACE inhibitors, ARBs, NSAIDs, diuretics

• Hypothyroidism, CKD

Key Investigations

• Serum Lithium Levels: 6-hourly if suspected toxicity

• Renal Function: Check creatinine, urea

• Serum Sodium: Assess for hypernatraemia (NDI)

• ECG: Possible QTc prolongation or arrhythmias

Monitoring on Treatment

• Lithium Levels: Every 3–6 months; target range ~0.6–1.0 mmol/L (1.2 mmol/L if manic)

• Renal Function & Electrolytes: Regular checks (UEC, CMP)

• Thyroid Function Tests (TFTs): 6–12 monthly

Management of Toxicity

Acute Toxicity

• Stop Lithium Immediately

• Hydration: IV 0.9% sodium chloride to promote lithium excretion

• Monitoring: ECG, serial serum lithium levels, renal function

• Haemodialysis (with toxicologist advice) if:

  • Serum lithium >4 mmol/L + renal impairment

  • Serum lithium >5 mmol/L

  • Severe neurological toxicity (seizures, coma)

Decontamination

• Activated Charcoal: Not effective (lithium not adsorbed)

• Whole-Bowel Irrigation: Consider if >50 g ingested <4 hrs earlier (toxicologist guidance)

Haemodialysis

• Continue until serum lithium <1 mmol/L and clinical improvement

Additional Notes

• CMP: Monitor calcium levels for hyperparathyroidism

• Avoid medications that reduce renal clearance (e.g. ACE inhibitors, ARBs, NSAIDs, diuretics) if possible

• Advise stable fluid/sodium intake to minimise fluctuations in lithium levels