Test or measurement | Frequency | Comments |
Lithium levels | 3 monthly | Additional levels should be taken 5 -7 days after any dose change, on admission to hospital or if there is a suspicion of toxicity1. |
Thyroid function | 6 monthly | Monitor more frequently if evidence of deterioration. |
Renal function (including U&Es, creatinine and calcium) | 6 monthly | Monitor frequently e.g. monthly if evidence of deterioration or if patient starts taking drugs known to affect renal function2. |
Assess for interactions | At every clinical contact | Review all drugs known to affect renal function. |
Routine side effect monitoring3 | At every blood test | Use the recommended side effect rating scale |
Weight | 6 monthly as a minimum and as necessary | Monitor pro-actively if patient gains weight rapidly |
1Toxic effects may develop within the normal range especially in older people. Toxicity should be considered if there are signs suggestive of dehydration, any change in mental or physical state e.g. confusion, falls or increased tremor.
2Drugs that may affect renal function and/or lithium clearance and hence may potentially result in toxicity if used with lithium include:
- NSAIDs e.g. ibuprofen, naproxen, celecoxib
- ACE inhibitors e.g. ramipril, enalapril
- Angiotensin 2 antagonists e.g. losartan
- Diuretics, especially thiazides (bendroflumethiazide)
If eGFR falls rapidly to <45ml/min review lithium treatment and refer to renal medicine. Investigate and correct for hyponatraemia or hypernatraemia.
3Common lithium side effects include:
- polyuria
- polydipsia
- nocturia
- diabetes insipidus
- metallic taste
- fine tremor