Lithium administered as lithium carbonate is used for the treatment of the manic phase of affective disorders, mania and manic depressive illness. It acts by enhancing re-uptake of neurotransmitters thereby reducing their concentration in the neuronal junction. This produces a sedating effect on the central nervous system.
Absorption of lithium from the gastrointestinal tract is complete, with peak serum concentrations reached in 2 – 4 hours after an oral dose. Serum lithium concentrations are monitored to assure patient compliance and to avoid intoxication. Early symptoms of intoxication include drowsiness, speech difficulties and twitching.
0.4 to 1.0 mmol/L: Therapeutic
1.0 – 2.0mmol/L: Moderately toxic
>2.0 mmol/L: Severe toxicity
NOTE: These values are applicable at 12 hours post dose
Serum or plasma from EDTA or sodium heparin
Specimen should be collected 12 hours post dose of lithium.