Lithium

Key points

• Lithium: mood stabiliser — narrow therapeutic index; target 0.5–1.0 mmol/l, sample 12 hours post-dose.
• Side effects: fine tremor, metallic taste, polyuria/polydipsia (nephrogenic diabetes insipidus), hypothyroidism, weight gain, ECG T-wave flattening.
• Toxicity (> 1.5 mmol/l): coarse tremor, confusion, seizures, arrhythmias — precipitated by dehydration, NSAIDs, ACE inhibitors, thiazides.
• Long-term monitoring: renal function and TFTs every 6 months.
• Severe toxicity → haemodialysis.

Decision points in this pathway

• Toxicity risk? (dehydration, NSAIDs, ACE-i, thiazides)
• Severe toxicity?

The full step-by-step algorithm, including what to do at each branch, opens in the app for approved members.