Monitoring lithium levels

Time to steady state - it takes four to five days for a steady state to occur after commencement of lithium (lithium carbonate or lithium citrate) therapy. At this time the first sample should be taken after starting treatment.

Therapeutic range (may vary with respect to different laboratories and therapeutic indication):

• once daily dose - at 12 hours, 0.7 to 1.0 mmol/l; at 24 hours, 0.4 to 0.8 mmol/l
• twice daily dose - at 12 hours, 0.4 to 0.8 mmol/l

Notes:

• NICE state that (2)
  • serum lithium levels should be checked 1 week after starting and 1 week after every dose change, and until the levels are stable. The aim should be to maintain serum lithium levels between 0.6 and 0.8 mmol per litre in people being prescribed it for the first time
  • for people who have relapsed previously while taking lithium or who still have sub-threshold symptoms with functional impairment while receiving lithium, a trial of at least 6 months with serum lithium levels between 0.8 and 1.0 mmol per litre should be considered

Reference:

1. Drug and Therapeutics Bulletin 1999; 37 (3): 22-24.
2. NICE (July 2006). Bipolar Depression.
3. NICE (September 2014). Bipolar disorder: the assessment and management of bipolar disorder in adults, children and young people in primary and secondary care