pharmacokinetics/interactions
Last reviewed 01/2018
- elimination half-life of lithium, in patients with a normal renal function, is about 20-24 hours.
- steady-state concentrations are reached about 5 days after commencing the drug.
- the glomerular membrane freely filters lithium, which is then reabsorbed in the proximal tubules with, and to the same extent as, water and sodium. Lithium clearance falls when the sodium plasma concentration is low, or the patient is dehydrated. Serum lithium concentrations are likely to be raised in a patient who has vomiting, diarrhoea, or excessive sweating, a patient on a low-salt diet, or a patient on a drug which reduces excretion of lithium e.g. NSAID, diuretic, ACE inhibitor.
Reference:
- Drug and Therapeutics Bulletin 1999; 37 (3): 22-24.